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    • #31258
      mountain4don
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      I often wonder if I am barking up the wrong tree when trying to shoot cast lead projectiles out of a firearm that was designed for a high pressure. Like casting for a 243 or 338 Win Mag VS casting and loading for 32-40 Win or 45-70 Gov’t. Should I just leave the high pressure rounds (60,000 psi) for jacketed bullets and use the lower pressure (less than 40,000 psi) for lead bullets? What is the common cut off pressure when you would move from cast lead projectiles to jacketed projectiles? And I do understand that you could shoot a 338 Win Mag at 25,000 psi for squirrel hunting.

    • #31261
      oldblinddog
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      I have a .338 Win Mag and a Lyman 33889 250 gr mold. I imagine that at 25000 psi it would make a dandy deer load. So many molds, so little time.

    • #31265
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      I’ve bumbled along and run 222,223 and 6.8 SPC up to nearly full speed . There is also the 358 Win .
      ​​​​​i don’t see any reason not to run cast in every cartridge . A step or stage slower powder and the heaviest bullet for the cartridge or that will stabilize and go for it . You might be surprised at how far you can twist a cartridge . 200 gr go surprisingly well in a 7.62 x 39 , only 18-1900 fps . 210s go well in 06′ . If a 308 will shoot it up to 190s will go nearly jacketed speeds . Now the super hotrods might be impractical 220 Swift or the Weatherby mags . Although the WM don’t seem to be out of reach .
      i guess it comes down to how hard you want to work at it and what you want the bullet to do to the target.

    • #31266
      Goodsteel
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      Pressure is pressure and we have almost infinite ability to effect it so I don’t think it has anything to do with it.
      Consider, we have shot cast lead bullets to 3200FPS in the XCB project using sub 30-06 case capacity cartridges.
      Most of the overbore cartridges would be perfectly at home shooting at these speeds with cast bullets, but you won’t EVER get there.
      Is it pressure as you ask in the OP? No. pressure would be lower and more controllable.
      Is it speed? No, anything 3000 FPS or less is game on for cast bullets.
      The only thing left is TWIST RATE. Yeppers. It’s the RPMTH again. By and large, the overbore cartridges are pushing long bullets to maximize the performance they offer at long range, from a barrel with a twist rate that will stabilize those javelins, which often puts your usable long range cast bullet speeds at less than 2000 FPS, which pretty much kills long range shooting in its tracks right away because you have a bullet with a horrible BC, traveling at a speed that will go transonic at 350 yards. (I.e.: epic crap chute).
      However, screw in a slow twist barrel that lets you push to 3000FPS, and now you can get that big case coughing the way it’s supposed to (or a heck of a lot closer than the alternative) and your transonic event is pushed back to 700 yards+, and you have the precision needed to shoot that fast and that far.
      You know, one of the proponents of fast twist shooting had me rebarrel a rifle for him. He told me to take a real close look at the throat of this 7mmAI barrel as he has shot “HV” with this rifle “over the threshold”. Well, I did look at the throat, and there was nothing to write home about. While I was at it, I measured the twist rate and found it was a 1-11 twist barrel. Exceptionally slow twist for a 7mm so no wonder.
      There are no exceptions. Like my dad used to say “I thought I was wrong once, but I was wrong”.

      That’s the magnificent takeaway from the XCB project. Cartridges that once were hamstrung by cast bullets can be useful if they are built correctly with a proper twist rate for the job, and it’s a very worthwhile thing to do because when you consider the gains in barrel life and usefulness with cheap cast bullets, coupled with the bragging rites (how many fellers do you know who lay deer in the shade at 350 yards with cast bullets from a 7mm Magnum cartridge?) it does fire the imagination.

    • #31267
      Goodsteel
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      Something else I’ll say is that most of these cartridges can be made to appear to shoot HV if you keep the range short. The whole point of HV shooting that many people miss, is long range hunting applications. What would be the point otherwise? The deer certainly fall over being hit by bullets traveling at 1800fps, and I proved the catastrophic effects of blasting them at close range with anything approaching HV. So the only logical reason for shooting cast bullets at HV, is long range hunting, and to literally be able to hit the target let alone kill it.

      So that brings us full circle to needing predictable HV precision with loads that shoot the same MOA (or maybe only slightly bigger considering atmospheric conditions etc etc etc) for any range.
      What you will find, is that loads made to shoot just under that point where accuracy goes to pot at 100 yards will not be predictable at long range. They open exponentially the further you get from the muzzle like the profile of a wine glass so you get 2″ groups at 100, 5″ groups at 200, 30″ groups at 300 etc etc etc. the only way to know that your load is predictable at long range is to SHOOT LONG RANGE. This is a problem. Most people shoot at a comfortable distance they can easily access, and try to predict what the load will do at longer ranges, which if you’re talking about a rifle that shoots blistering HV groups with cast at 100 yards, but follows a wine glass stem shaped degradation of precision at longer ranges, could be humbling in the extreme, or might even cause undu suffering to the game animal.
      Im reminded of a humorous conversation I once had with another “HV with standard twist rate” proponent, in which he admitted to me that all of his testing had been done at 100 yards or closer, but he had been afforded the opertunity to shoot on a much longer range. He said he couldn’t even get a shot on the backer at anything past 200 yards with his 1MOA at 100 yards HV load. He went on to say that he was determined to find out what the cause was, but he knew that it wasn’t the RPM threshold………
      So it continues that nobody who claims HV shooting over 144,000rpm is willing to show groups at extended ranges, which begged the question of why they want HV, if they cannot practice in the only situation where it makes sense to use it. Meanwhile Larry Gibson has provided many examples of 300 yard groups that demonstrate rock solid MOA figures per yardage (in fact, he was doing it mere weeks after he received the rifle I built for him).

      So you see, ANY of these cartridges can shoot cast bullets at blistering speeds (faster than the same cartridge loaded with jacketed in fact) you stoke a case full of powder behind a projectile, something is coming out of the barrel really dam fast. The rub comes in when you try to get those bullets to exhibit a predictable level precision at longer range. So you have to be sceptical when folks claim fast speeds at less than 100 yards. Most of them are hoping nobody asks how that load does at longer range, and they get REALLY irate when you ask if their load is good for more than hitting the air over a chronograph.

      If you want to use high performance cartridges for cast, you need a slow twist barrel. Keep the RPM less than 144,000 and it’s game on.

    • #31272
      Rattlesnake Charlie
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      Goodsteel, what actually happens to a bullet at over 144,000 rpm that degrades accuracy? I would think at some point it flies apart from centrifugal force, but then you would not get any holes in any target.

      And, how was this value discovered?

      I’ve pondered these questions, but never found succinct answers.

      So far, I’ve never launched a cast bullet faster than 2450 fps, and that was out of a Lee Enfield Mk4 No 1. I could match ball and even factory soft point accuracy, but that wasn’t saying much with paper plate sized groups at 50 yards being about the best it ever did. I do hope to start loading cast for my .308 this winter. So many projects, so little time.

    • #31274
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      Maximum length for twist , less violent launch , well fitted bullets , stable platform, goods delivered.

      I agree that something happens when a speed either forward or rotationally is reached . Some cases simply don’t allow enough room to make it happen . I’ve seen the 4000 fps 22-250 bullet poof . I’ve seen an 06′ through a cast bullet apart ,and I wonder why it doesn’t happen in Mosins . In a 14″ twist the typical 69+ gr 22 cal bullet even in a Swift doesn’t have enough case to reach stability . Back it off the a 62-65 gr cast or 55 gr jacket and walk the wire . Back it off to 55 and 50 and it’s easy . In nominal shapes of the respective bullets of course .
      An 8.5-9 twist in 308-312 grooves is fast twist and reaches the rotation limit of the bullets at a relatively low speed . Early on in my cast adventures I loaded some work up loads from the books with factory cast .(there were a lot of things wrong with the loads other than the example here) As the loads progressed they went from 8″ to 4″ to off the board to grey trails to a shattering glass sound to a white cloud probably about 10ft from the muzzle. Unique in an 06′ really shouldn’t do that . I have no way to speculate what the velocity might have been but I’m certain that they were beyond the structural integrity of the bullets. Same rifle 150 gr jackets 2600 fps with its measured shorter than 9″ twist 5 touching at 100 out to 250 measured still inside an inch CTC . Beyond 400 the drop became more the problem than the 4.5″ Group. Take a step just .3 gr the load goes to 1″ CTC and 2675 fps. Go a half gr and break 2700 fps now you have 3″+ by 2750 it’s barely a 00B pattern . The next work up will be with a 230 reaching for 1700 + not a real lofty goal but the SP 200 would only make 1800 before it either collapsed or over spun . Harder alloy allowed higher speeds but I really believe the nose slumped because just a tiny step in speed resulted in groups that leaped from 2″ to where’d it go. 300 yd hits on a man steel were easy with the 17-1800 fps loads .

      Funny thing about the rules and the standards we find . There is a 12 twist 308 , it shoots a 150 BTSP very well 168s also but it won’t shoot a RN 180 the same length as the 150 anywhere in the load window. It even keyholed a load . The 12 twist 30-30 while not showing a group makes perfect round holes with the 312-230 . An exception to every rule . Yes the rifles I’ve loaded for have demonstrated all of the proofs . They also have shown me that a single point ,perhaps facet, isn’t the only fail point but rather that that facet is a meeting point of other facets . Rev limit is that major facet and we can’t make it go away but we can move it around and to some degree even make it work for us .

      If the hole is in the right place a critter is just as dead with a 1.25 inch slot from a 35ftlb arrow as a 3000 ft-lb half inch hole from a 45-110 or a 458 WM .
      ​​​​​

    • #31277
      Goodsteel
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      Rattlesnake Charlie;n11326 wrote: Goodsteel, what actually happens to a bullet at over 144,000 rpm that degrades accuracy?

      I cannot answer that. I have theories, but nothing concrete. I’m hoping that the high speed photographs will yield some better understanding of WHY, but anyone who tries to shoot fast can see this happen.
      Some say you can move around the RPMTH. I dare say those people do not shoot one inch further than 100 yards, and most shoot at 50. Usable HV long range shooting? Hardly.
      Larry says the bullet is damaged in the throat at launch. That seems unlikely to me (with all due respect) and I dissagree. I feel that this is a dynamic problem and the bullet gets loaded with stress which is held in place by the rifling and released upon exit and the bullet relaxes in flight, but I have no more proof for my opinion than anyone else, because I’m looking at the effect and trying to judge the cause by the evidence, which is shaky ground.
      That does not change the fact that predictable long range loads do not exist over 155,000RPM, or at least, I’ve never seen it, and I paid dearly for the opportunity to do so, and/or be shown even in PM. The only way that has worked and has been properly demonstrated is a slow twist barrel.

      Rattlesnake Charlie;n11326 wrote: I would think at some point it flies apart from centrifugal force, but then you would not get any holes in any target.

      This is actually very rare as (unlike jacketed bullets) cast bullets are homogeneous and solid. I’ve heard tell of bullets breaking in two before (like that embarrassing time one of the guys who was trying that colossal failure called the “cruise missile” shot his truck when the bullet flew apart.) most of the time, when the RPMTH is crossed, you get round holes in the target that are widely dispersed.

      Rattlesnake Charlie;n11326 wrote:
      And, how was this value discovered?

      I believe it’s been discovered by everyone who wanted to shoot an antelope through the heart at 300 yards with cast bullets, but Larry Gibson was the person who tried it with enough rifles that he saw this shockingly consistent pattern.

      Rattlesnake Charlie;n11326 wrote: I’ve pondered these questions, but never found succinct answers.

      I ponder them too, but I’m paying the piper for my answers and conducting my own research and leg work, because most that say they have a solution have a very big axe to grind and are not interested in the science. Me, I pitch over easily wherever the facts lead me, and in this case it wasn’t too hard. There’s a lot of people out there who are much better at interpreting their groups than they are at reporting them.

      Rattlesnake Charlie;n11326 wrote:
      So far, I’ve never launched a cast bullet faster than 2450 fps, and that was out of a Lee Enfield Mk4 No 1. I could match ball and even factory soft point accuracy, but that wasn’t saying much with paper plate sized groups at 50 yards being about the best it ever did. I do hope to start loading cast for my .308 this winter. So many projects, so little time.

      I wouldn’t put too much stock, nor try to draw any deep truths from a rifle that shot cast as equally bad as jacketed. LOL!
      Consider this also: I can shoot a 2″ group at 50 yards with my 12 gauge smoothbore shotgun using round balls. If I’m not cutting a ragged hole at 25-50 with a rifled barrel, then there’s something horribly wrong with the load or the rifle. 100 yards is the point where you start to see if the load has promise, and it’s an excellent range to work up loads at because it’s still close enough for the wind not to have too much effect (especially assuming you are shooting HV cast).

    • #31291
      mountain4don
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      Most of what I reload lead bullets for are rather antique rifles and cartridges. Are there any written resources or books around that might give suitability charts for different calibers, twist rates, pressures, bullet sizes and such for lead bullets? Or do we just have to try stuff until it works and then determine if the load is suitable for what we want to do? Of course I have been casting bullets and shooting these rifles for 40 years now, and have just stumbled on certain ones that work much better than others. And experiments of others have been a big help since these type web pages on the internet were developed. But I always have my old standby calibers and rifles that always seem to shoot well with lead bullets. The 30-40 Krag, 45-70, 32-40, 303 British, and the 7.5×54 MAS. The difficulties with extremely fast twist barrels have eliminated some of the rifles like the Swedish Mauser and the AR-15 with its 1:7″ twist. Although both of them can be made to shoot at relatively slow speeds for plinking accurately or squirrel hunting. But I wouldn’t even try a cast lead bullet for that 300 yard shot at a coyote with that AR-15.

    • #31295
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      100yd is about all I would ask for from a fast twist 223 especially in an AR . Especially in the bargain basement bin specials for which I’ve loaded . They were 1-8 for the record . I think probably a 1-10 would do everything a 223 needs to do ,but that’s me thinking so grain of salt and all that.

      I would think if you get good to great loads in a Krag that you will master the other 30 cals up through about 1960 without any particular problems.

      Twist is the most expensive part of casting to fix , $100 moulds or $400 barrel refits.
      I can’t help beyond making the most of what you have to work with . I’ve been pleased with using the heaviest bullet one can feed a twist . For example if you like me have a fast twist 30 that you have an alloy ceiling speed limit of 1800 fps a 210 gr bullet like the 312-230 NOE will meet the arbitrary 1000@100 number but the cartridge and twist would allow you to go probably 1600 with as much as a 250 gr bullet . Past about 225 gr however your kind of on your own to find data . In such cases if it’s too slow to hit make peak pressure in the rifle with a full compressed load it’s a good place to start. Safety first . Custom mould or a new barrel will make the most .
      Likewise with the 223 ……..the gas system however plays here too making it even more challenging . I’d have no idea where to look for an 80+ gr 22 cal mould, but if you find one I’d expect it to resemble 260-120 fp NOE but at 225-82 FP maybe there is a SIL bullet . Then you have to play the powder game even with an adjustable gas block it will be a fine line to find a great load, that’s not over gassed and have a fast enough powder to hit velocities. Sometimes it’s not worth the effort . Sometimes the reward is over the moon .

      I ran a 6.8 Rem SPCII . Bought the 279-124 NOE , my alloy drops at .279 and 129 gr , 131 lube and check . Bonus points it comes in 1-11 twist . Slow for 270 cal. It runs right up to jacketed start speeds , and if it had been an 18″ barrel with rifle gas instead a 16″ mid it would make it . 2100 fps 4″ at 200 and sense that betters the best shelf loads I tried I’m good to go.

    • #31303
      mountain4don
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      I very much appreciate the technical discussion here about selecting cast bullets and possible velocities for them. It is very informative. My main interest in all of this is the collecting of antique firearms and shooting them accurately. And of course I am not going to put a custom new barrel on a 100 year old gun to “correct” the twist rate to better shoot cast bullets at higher velocities. I want to shoot cast bullets accurately in old soft steel barrels to keep from damaging them. But also to be able to shoot them accurately enough to use them for deer hunting in ranges up to about 300 yards that I have available out across the soy bean fields. On the other side, all of these antique, mostly military weapons, have rather limited sight systems that limit what I can do with it. And of course I don’t want to damage a rifle by drilling and mounting a scope. But of course, both my 338 Win Mag and the AR-15 both sport scopes for those long range hunting shots, prompting the questions about pressure limits for loading cartridges to shoot in these. I have shot deer at 300 yards with a 29″ barrel Swedish Mauser in 6.5×55 using a clamp on sight blade in front to “fix” the sight picture using 129 grain jacketed Hornady bullets. But I could never get my cast bullet loads up to enough speed to shoot that far effectively or accurately with the rifle. So that is one of the calibers that seem to elude my attempts at longer range shooting. It makes a good squirrel rifle though at short ranges with lead bullets and lower velocities. I really want to try cast lead bullets in a Winchester 94 in 356 Win caliber because I think that one has potential, and it also has a scope for longer range shooting. But unfortunately thats my wife’s deer rifle and she doesn’t want me fooling with it.

    • #31304
      Goodsteel
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      mountain4don;n11375 wrote: I very much appreciate the technical discussion here about selecting cast bullets and possible velocities for them. It is very informative. My main interest in all of this is the collecting of antique firearms and shooting them accurately. And of course I am not going to put a custom new barrel on a 100 year old gun to “correct” the twist rate to better shoot cast bullets at higher velocities. I want to shoot cast bullets accurately in old soft steel barrels to keep from damaging them. But also to be able to shoot them accurately enough to use them for deer hunting in ranges up to about 300 yards that I have available out across the soy bean fields. On the other side, all of these antique, mostly military weapons, have rather limited sight systems that limit what I can do with it. And of course I don’t want to damage a rifle by drilling and mounting a scope. But of course, both my 338 Win Mag and the AR-15 both sport scopes for those long range hunting shots, prompting the questions about pressure limits for loading cartridges to shoot in these. I have shot deer at 300 yards with a 29″ barrel Swedish Mauser in 6.5×55 using a clamp on sight blade in front to “fix” the sight picture using 129 grain jacketed Hornady bullets. But I could never get my cast bullet loads up to enough speed to shoot that far effectively or accurately with the rifle. So that is one of the calibers that seem to elude my attempts at longer range shooting. It makes a good squirrel rifle though at short ranges with lead bullets and lower velocities. I really want to try cast lead bullets in a Winchester 94 in 356 Win caliber because I think that one has potential, and it also has a scope for longer range shooting. But unfortunately thats my wife’s deer rifle and she doesn’t want me fooling with it.

      Well, the reason you can’t get that sweed to shoot very fast is because of its incredibly fast twist rate (1-8 or 1600FPS)
      Or the 338 Win Mag (1-10 or 2000FPS)
      Or the AR-15 (1-7 or 1400FPS)
      Or the Blackout (1-8 or 1600FPS)
      Or the 8mm Mauser (1-9.5 or 1900FPS)
      Or the 7mm Mauser (1-8.7 or 1740FPS)
      etc etc etc.

      Many people can beat these numbers at 100 yards or closer, but if you’re trying to call your shot across a bean field??????? Good luck.

      I totally understand not wanting to change anything on an old military firearm, but unfortunately, most of them need to be launching jacketed bullets if you’re going for the long toss.
      Be careful about stuffing in cast bullets that are too long for the application. Two things will happen if you do this.
      1. The bullet begins to slump and exacerbates the RPMTH effectively LOWERING it even more, and
      2. The bullet might be going slow enough that it hasn’t got the RPM necessary to stabilize it in the first place. There’s a point where all the compromises catch up to you real sudden like.

      Shooting long distance with cast bullets is a real trick, and I think if you were going to atempt it, without building a HV rifle for the job, you would be looking at black powder 45 caliber rifles with REALLY slow twist rates.
      OR……….
      Pick a caliber that hasn’t gotten bit by the ultra fast twist bug. Something that shoots a heavy bullet, but can also be pushed FAST without killing on both ends. Something that is easy to get brass for and practice with.
      There’s a reason the 358 Winchester is considered one of the greatest cast bullet cartridges of all time. Get that in a well constructed rifle and you can toss across the bean field and have enough pop left when you connect to put a deer down.
      With a 14 twist barrel, the RPMTH is about 2600FPS, but you’ll never get to it with the small case capacity, so basically a cast bullet will handle whatever that cartridge dishes out.

    • #31312
      popper
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      Cast at HV
      1) As stated previously, Cast at HV at long range is the real goal.
      2) Boolit shape, BC, SD, alloy & twist are the selection criteria.
      3) Army has a facility to track the Helix path of trajectory. Perfection would be an on barrel axis with only gravitational drop vs fps to consider. The test deflects a bullet to create the Helix path, actually measured as it penetrates mu ltiple targets at different distances. Fps is varied to generate various rotational RPM. The test is to determine how much spin is required to damp/eliminate the helix path. It is also used to test over-spin vs desired tumbling at the target.
      4) non-linear dispersion (primarily) is the effect of gyro action that dampens (stops) or over-dampens (restarts) the helix. Of course a strong FMJ is used for the tests. We use weaker lead alloys that, if deformed or not symmetrical, will be affected by spin. We use stronger alloys to defeat this effect. We must remember that high gyro momentum will cause that energy to re-direct the path of the boolit aggressively! Yes, it may go poof.
      5) BC/SD. From Sierra data, RN & FP boolits may have high BC at lower fps, BC decreases around 1400 fps. Pointy boolits and heavy for cal. have higher BC, i.e. lose less fps.
      6) We only have a few paths for solution. One is slower twist. One is better (harder/tougher) alloy. One is pointy boolits. Twist and alloy are pretty well known, shape can be the bugger. Blunt for impact, sharp for penetration? Soft for expansion?
      7) Alloy is not much of a problem for slow blunt boolits but is a great concern for high BC pointy boolits at HV. We want HV for long shots & good terminal ballistics on the target.
      8) Easiest solution is a good jacketed hunting bullet.

    • #31314
      Rattlesnake Charlie
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      Wow. This is getting deep.

      “8) Easiest solution is a good jacket hunting bullet.”
      I’m gonna have to think on this one. My .45-70 seems to do OK.
      I do like that we can offer differing ideas here in civility.

    • #31316
      mountain4don
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      Rattlesnake Charlie;n11390 wrote: Wow. This is getting deep.

      “8) Easiest solution is a good jacket hunting bullet.”
      I’m gonna have to think on this one. My .45-70 seems to do OK.
      I do like that we can offer differing ideas here in civility.

      Well, our object is in learning about the firearms we use, and what their limitations or optimal uses may be. I probably already knew that my AR-15 in 223 with a 1:7″ barrel is optimal with 70 grain jacketed bullets for those 300 yard shots at coyotes across the soy bean fields. And my 45-70 is ideal for deer up to about 200 yards if I lead them far enough if they are walking, or the wind is blowing. But the antique military rifles are all kind of a mix of capabilities at different ranges that are fun to play with using cast bullets. To see what I can make them do. And with some practice I can decide if they are good enough for deer hunting or squirrel hunting and what range I can use them at effectively.

    • #31320
      Larry Gibson
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      “Larry says the bullet is damaged in the throat at launch.”

      While that is true to a degree it is an oversimplification. As I’ve said many times learning about and understanding what is the root cause of the RPM Threshold, especially with cast bullets, has been a continual learning curve. Yes I am the one who first saw and reported the connection that loss of accuracy with cast bullets was directly related to RPM at a certain level (generally 120,000 – 140,000 RPM). However since that first revelation a better understanding of what causes the RPM Threshold has happened. This has occurred because we have continued to experiment, test and measure (velocity, pressure and down range accuracy). As we continue testing new revelations about what is occurring come to light.

      Since I have been measuring the time/pressure curve in numerous rifles of varied cartridges and twists I have now a better understanding of what is happening during the internal ballistic phase of the bullets flight. Because of fairly recent other experiments and test I now believe the cast bullet is damaged, i.e. unbalanced, not only during the bullets entering the throat and being swaged and engraved to fit the internal barrel dimensions but also during the entire rise to peak pressure period of acceleration. Additionally we now also know the bullet is swaged down .002 – .005″ less than the groove and bore dimensions by the lube it must pass over in the barrel.

      I also noted early on that the RPM Threshold for a given bullet of a given alloy could be moved up or down by changing the powder to a faster or slower powder. Many years back it was peak psi and the strength of lead that was used in theory as to why cast bullets became inaccurate at a certain level of psi. This was exemplified by Richard Lee in his loading manuals. However, since the use of peizo-transducer and strain gauge pressure measurement systems became available they have given us a much better picture of the actual pressure occurrence in the chamber/barrel. That knowledge has enabled us to now understand that psi has little to do with the loss of accuracy as velocity increases. It is the acceleration rate (time/pressure curve) and the level of attained RPM that are the determining factors. The first has a direct influence on the damage done to the bullet and the latter determines the point at which that damage causes the bullet to exceed the RPM Threshold.

      Using the .308W cartridge for example in rifles of 10, 12 and 14″ twist I have increased the velocity from 1950 fps to 2400 fps to 2600 fps (+/-) respectfully while maintaining sub 2 moa (most often 1.5 or less moa) accuracy out to the tested 300 yards. Of course increased velocity in the same cartridge with the same bullet requires an increase in psi. The psi’s have run basically 28K, 35K and 48K respectfully. With the 16″ twist 30×60 XCB the 1.5 moa or less accuracy level has been maintained to 2950 fps with psi’s running 50 – 52K. The psi in each rifle was measured via an Oehler M43 PBL.

      I don’t think anyone here is telling anyone they have to rebarrel any rifle to shoot cast bullets accurately. I shoot a lot of cast bullets out of my milsurp and commercial rifles with excellent accuracy. The trick to that is just to keep the bullets under the RPM Threshold. That is exactly what 99% of cast bullet shooters are doing. This year I won the Arizona State CBA Military Rifle Match using a Finn M39 shooting the 314299 at 1850 fps, well below the RPM Threshold.

      What is said here is if you want to shoot a cast bullet in a .308W (example) at jacketed bullet velocities accurately then you can come close with a 12 or 13″ twist factory rifle. However, to shoot cast bullets accurately at actual factory jacketed velocities will require rebarreling with a 14 – 16″ twist barrel. That too is an over simplification as you must use a cast bullet of appropriate design, cast it of appropriate alloy, learn how to cast an excellent bullet and learn how to load it properly along with a few other nuances that are not hard to learn.

      Bottom line is that psi has little to do with loss of accuracy, Loss of accuracy as you increase velocity and psi is caused by the centrifugal force at a certain RPM acting upon imbalances in the cast bullet in flight. Where accuracy is lost is the RPM Threshold.

      Larry Gibson

    • #31322
      popper
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      You load 45-70 near 60Kpsi? Fps is closely related to psi. Per Tim’s thread, you need pressure and fps for long shots. I was perusing BC of NOE 30 cals. 30xcb=.286, 165RF=.3356, Elco(SP)=.3827, 150Sp=.42, BO=.536. So the 165RF is a good HV boolit? Nope. IMHO, my comment still is valid – it is easier to shoot HV (pressure) at long distance accurately with a jacketed SP. Not arguing with the RPM either, it’s just ONE factor in cast shooting and is mostly related to boolit quality.

    • #31323
      Larry Gibson
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      Popper

      If you’re asking me if I shoot a 45-70 near 60K the answer is; yes I do and that’s with both jacketed and cast bullets.

      Rifle is what I call a 450-400-70 built on a Siamese Mauser action. I push 400 gr jacketed to 2200 – 2300 fps at 60 – 62 K psi. I push the Lee C457-500-FN at 2050 fps at 58K+ psi and the Lyman 458483 at 2300 fps at 59K psi. The pressure measurement is done on that rifle with the Oehler M43 PBL.

      Given the 20″ twist the RPMs are 73,800 to 82,800……well below the RPM Threshold. Since the rifle weighs in at 8 1/2 lbs shooting for accuracy off a bench is brutal to say the least. However the loads mentioned were good for 5 shot 1 1/2 – 2 moa through 200 yards.

      Larry Gibson

    • #31324
      Rattlesnake Charlie
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      Larry, brutal might be an understatement. I don’t enjoy shooting 350 gr bullets at Trapdoor velocities out of my 1895 Marlin Cowboy. They must be mild compared to what you are touching off.

    • #31325
      Larry Gibson
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      Rattlesnake Charlie;n11406 wrote: Larry, brutal might be an understatement. I don’t enjoy shooting 350 gr bullets at Trapdoor velocities out of my 1895 Marlin Cowboy. They must be mild compared to what you are touching off.

      A few times after the 2nd or 3rd shot I wonder where that Joe Frasier left hook is coming from……..

      I mostly shoot lessor loads such as the 500 gr cast at 1750 fps which is good for the larger antelope or any miscreant lion or tigers that might show up. The 458483 I load right at 1500 fps baboons, jackals, hyenas and lessor game………..ah, I do have my hallucinations……….:rolleyes:

      Larry Gibson

    • #31326
      Goodsteel
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      I don’t think anyone here is telling anyone they have to rebarrel any rifle to shoot cast bullets accurately.

      Certainly not. It’s just the best way to answer the situation as it was laid out. Long range hunting with a medium recoiling, flat shooting rifle using cast bullets was the practical underlying “what do you do with it if you succeed?” motivation for the XCB project. Larry, you mentioned popping antelope at three hundred yards. My hunting area at that time had me set up on a power line easement with a 400 yard field of view and I was the only one in the club that could shoot that far, so I wanted it with cast bullets. Others who have ordered custom rifles from me had similar needs.

      Fact is, any way you slice it, if you want to shoot “a fer piece” with cast bullets, the deck is stacked against you. The options are slim and they all cost a lot.

      One way is to do as Harter66 mentioned: use heavy bullets and push them as hard as you can while maintaining precision. That’s easy to talk about around the camp fire, but I’m one of the guys who’s crazy enough to make that happen and I’m here to tell you, you might as well start buying your primers by the case, and your powder by the 8lb jug, and plan on redepositing 200-300 pounds of lead into the earth at long range. It’s going to take a LOT of practice to learn the bullet drop and the wind drift to where you can call your shot.

      Another way is to have a custom rifle built. There’s $600, but then you know exactly what mold, what powder, and how to prep the brass etc etc etc because you can holler and any one of us who have done it. Pay me now or pay me later. I dare say you get there with a little more class this way, but it still costs.

      Finally, the more direct option: This does not require you buy lead, molds, lubes, custom rifles, range fees, gas to the range, etc etc etc. There is a process to it, but follow these directions and you’ll be fine:
      1. Start your truck.
      2. Drive to walmart.
      3. Stride forth with vigor and gusto till you find the gun counter.
      4. Find an associate to help you with your purchase.
      5. State to said uniformed Walmartian that after careful consideration of all the paths you could take that would render you successful. All the data compiled and condensed to a single motivation. All the opinions of your worldly associations both in person and online, and all the costs carefully counted and weighed against the alternatives………..

      you would so very much appreciate it if he’d just sell you a $20 box of “bullets” so you can use three of them to shoot the freakin deer and get on with life.

      Once back in your truck, hold that gorgeous yellow and green box of Corlockt’s and as a tear rolls down your cheek, just take a minute to give thanks to God that:

      You get to call them “bullets” and the deer don’t give a rats rear end if you call your magazine a “clip”.

      That you didn’t have to burn a single brain cell on how the projectile is shaped, nor if it matches your twist rate correctly.

      That you were never required to consider what propellant lies between the primer and the bullet, nor where it falls in the burn rate chart.

      That the thought of becoming the bullet smith never entered your mind and you never had to learn how to cast a perfect bullet, only to realize you had the wrong one, or that your alloy was substandard, or that your bullets were too hard, too soft, too long, too short, or had too many lube grooves.

      That dad’s rusty ol 30-06 has been killing deer at 300 yards and closer for 50 years with the ol green and yellow box ammo without your stepping in an “improving” things.

      You have all the time you want to spend fishing, collecting stamps, or traveling.

      Your wife never had to explain to the neighbors that you have a mental condition when you got caught prying the wheel weights of their car mumbling “Wow it’s a REAL one!!!”.

      That you have a garage…..and your wife can park her car in it.

      ALL of this brought to you…….by a $20 box of factory ammo.

      I swear i’m getting all misty thinking about living such a simple alternative.
      Bah. I’m a bullet caster. I don’t have time to trifle with weird thinking like that.

    • #31327
      Rattlesnake Charlie
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      Goodsteel;n11408 wrote:
      Once back in your truck, hold that gorgeous yellow and green box of Corlockt’s and as a tear rolls down your cheek, just take a minute to give thanks to God that:
      ….
      That you have a garage…..and your wife can park her car in it.
      ….
      Bah. I’m a bullet caster. I don’t have time to trifle with weird thinking like that.

      Hey, I happen to think Core-Lokts are really good for deer hunting.
      My truck doesn’t rust when it gets covered in snow like my reloading press does.
      Yup.

    • #31328
      Rattlesnake Charlie
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      Larry Gibson;n11407 wrote:
      ……….ah, I do have my hallucinations……….:rolleyes:
      Larry Gibson

      It is from the gun smoke. Happens to me too. Down right addicting. I need another hit ….

    • #31331
      popper
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      I can’t even handle 12ga slugs from a 5# single shot. With those heavies you have good SD which generally gives a good BC. SD is effectively a gyro equation parameter, higher means better.

    • #31414
      Smithbrosarchery
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      Popper’s post #13,(3)….cycloid question.

      Do bullets “ever” fly in a single plane?Looking at the trajectory arc,connect start point(muzzle)….stop point (target)…..now go anywhere along the trajectory arc.Is this all in one plane?Take wind out of the question for right now.Is that what cycloid is referring too?The notion/idea that it is “not” a flat plane.The bullets path is in two planes?

      The reason I ask….years ago we were shooting 200g H&G swc outta .45 acps.We were getting our kicks shooting at clays on a 80-100 yd berm.At certain times of the day,I at least,could see the Suns reflection coming off the bullets base….usually,picking it up just before the halfway point twds clay.They were flying in a curve….cycloid?….Up and over to the left,curving back into the aiming point.At least to me,it was plain as day……and could “walk” the bullet right into the clay.

      I’ve won archery tourneys with “bent” arrows.At some point down range the velicity and twist rate of arrow stabilizes and “goes to sleep”(and no,not promoting shooting bent arrows).Is this happening to a bullets path?

      Had to use our computer,the phone dosn’t work well with the responses on this site.I can read fine on phone,its the reponses that are dang frustrating….the “type in” window dosen’t scroll with the response.Well,I could “grunt”….”nice rifle”,”nice group”‘etc.But anything more than 2-3 lines is typing in the dark.

    • #31424
      popper
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      Smith – your arrow analogy is correct. Bullets can go to sleep or wake up or both, That is what the OP are saying is linear dispersion, waking up. Larry is talking spinning too fast and imbalances in the boolit cause wobbly – creating gyro procession (helical spiral path). The boolit can go in a single plane. Slow motion video of arrows shows they wiggle. Your curved arrows just wiggle in a known way. There is a video from a while back showing 22LR with various damaged noses and the path they take.

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