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    • #24153
      Goodsteel
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      Here’s a cross section of the Hornady check and you can easily see the bowed up center section and the lackluster “crimp” edge on them.

    • #24155
      Goodsteel
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      The trailing edge of the GC is much more important than the leading edge. The problem is that flattening the leading edge does practically nothing to square up the trailing edge. The GC’s are formed through a bunting process where the disks are stamped out and a very heavy impression is made in them, after which , the cup is formed rendering the “crimp on edge” on the inside of the cup.
      The material in the bottom of the check is of consistent thickness, but is bowed like a potato chip, which effects the outer edges (the trailing edges). The rim is very difficult to make a consistent hight from the bottom of the check, as material flows up one side of the punch more or less than the other side.
      By sanding the leading edges of the checks, we correct one issue, but this has very little effect on the part that really matters: the trailing edge.
      If we sand the check’s leading edges and measure them with a .0001 indicator we can see how uneven the base of the checks really are:

      In this case we have about .004-.005 variance across the base of the checks.

      This is very easy to observe if we flip the checks over and apply some blue layout dye to the backs of the checks (you can literally see the odd and uneven curve of the bottom surface of the checks):

      Then sand them lightly with the precision block and sandpaper:

      So if we sand further and actually flatten the side that matters to groups, the warped, dished, and inconsistent base becomes flatter and flatter.

      And measureing the check with the .0001 indicator shows near perfection with a TIR of less than .0002 (that’s 1/40th the variance present just flattening the leading edge. Not too shabby.

      Obviously the problem here is that even though I uniformed the OUTSIDE of the check, the INSIDE is still bowed up like we see in the original picture and does us no good because when seated against the base of the bullet the check will dish OUTWARD and as we see in the sanding picture above, that will never be consistent.
      So, I decided to design a method to uniform the checks before sanding in an attempt to preserve a concentric radius around the edge of the check.
      I selected a piece of 0-1 tool steel from the rack and turned a nose on it that precisely matches the shank of the NOE 30XCB bullet as cast from linotype (since this alloy renders the largest bullet, and thus the largest GC shank). Actually I made it about .0004 larger in diameter to allow for some spring back shrinkage.
      This tool was mounted in one of the tool holders for my milling machine, and the tip was sanded flat to the presision surface it was touching by pulling a piece of 400grit sandpaper between them with the cutting side up. The tool was cleaned, and the checks were pushed onto the nose, and the tool was brought down hard about three times on this piece of precision ground cast iron in order to swage and flatten out the uneven surface of the check.
      On the third bump, I hit the switch that turns on the spindle and held pressure for a second before raising the quill, and turning off the spindle.
      The checks were then wedged off the nose of the tool with a pair of cheap needle nosed pliers I ground and polished for the job.

      The positive results were easy to see when compared to an unmodified check:

      The checks were painted with blue dykem and rubbed on the granite surface plate to see how flat they might be. Turns out there is a slight crest to the check which is not surprising considering the method I used to flatten the nose of the tool. I really don’t care as long as it is concentric and flat and it is certainly that.

    • #24157
      Goodsteel
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      Next, I flattened the checks by sanding them using the tape method above (now I am satisfied that I am actually sanding to a controlled surface) and checked them with the .0001 Interapid. I measured no more than .0005 TIR. One tenth the variance they had as they arrived.

      Finally, I tried them on the Linotype bullets and was pleased to find that I could push them all the way to seated depth with my thumb, and the resistance was superb. Checking the bases for squareness revealed that I attained better accuracy using this method than I ever was able to do with the best seating devices I have ever created.

    • #24160
      Goodsteel
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      I took the Felix rifle to the range and got to put her through her paces. I really wanted to satisfy myself that the GC uniforming tool was a worthy investment of my time, so I loaded up 40 identical cartridges, with the only difference being the method of preparing and seating the GC.
      All cartridges were loaded with 53 grains of WC867.
      All cases were SL 43 military. Sized first with the 358WCF die, then with the XCB die. Case necks turned for a tight slip fit with a .310 bullet.
      Primers were CCI LR
      All bullets were cast by Sgt.Mike and sorted by weight and for visual defects (verified here at MBT).
      Lube used was White Label 2700+
      Bullets were sized to .3097
      Seated for a light press fit to the throat.
      The only difference was in the GCs as follows:

      20 bullets were lubed with RCBS case lube.
      GCs were seated with a custom MBT die blank with a GC sized pocket that keeps everything in alignment while the bullet is pressed into the check with the ram. Then the bullets were run through a custom MBT modular push through sizing die to a diameter of .3097.
      Afterwords, the bullets were dip-lubed and run through the die a second time.
      Finally they were seated in the brass.
      These are the ununiformed GC bullets.

      20 bullets were lubed with RCBS case lube.
      The GCs were uniformed on the MBT mandrel as outlined earlier in this thread.
      They were uniformed with a mandrel that measures .2873 and then plucked off the mandrel and used. No care was given to flattening the tip of the mandrel, nor making sure it ran true. In fact, I purposefully made sure it was wobbling in the tool holder to simulate someone doing this on a drill press. Also, no sanding was done, and there were tool marks left on the leading edge of the check from the pliers (it was a little harder to get them off this larger sized mandrel).
      The checks were easily placed on the bases of the bullets with finger pressure (they would barely stay on the bases) and then the bullets were run through the .3097 die.
      The GCs were securely installed and the bases were amazingly flat and square.
      The bullets were then dip lubed, and run through the die a second time.
      Finally they were seated in the brass.
      These are the uniformed GC bullets.

      It was a gorgeous day at the range! The light was superb, and the breeze was coming in gusts directly from 6:00. Temperature was 50 degrees and just a might chilly.

      First, I shot the nonuniformed GC bullets.
      Speeds for all shots ranged between 2235 and 2263. I did not keep exact records because that was not the purpose of this range trip, and speed was not what I was after. most shots fell within +-10 FPS of 2250 except one which made it all the way to 2294 and went wild. Strange.
      These were the first shots with the new rifle using BjornB’s old barrel:
      (My shot string was interupted by the resident range nazi, but this was only to get on paper)

      Once firing recommenced, the barrel was ice cold, and the first shot went low left. After that, I fired a ten shot group into the center of the target and established a group for the nonuniformed bullets.

      After this, I switched to the uniformed GC bullets and fired a ten shot group at another spot.
      (the marking you see in the lower left part of the picture was that strange flier I mentioned earlier. The speed was much higher than the other shots, so I could only assume there was something wrong with that cartridge for some reason)

      Finally, I fired one last group of eight shots (ten minus the weird one noted above from the previous group, and one that was demilled upon extraction when the range nazi called time).

      My conclusion from this range trip was that I will be uniforming all the GC’s that I will be shooting HV with. It made a noticeable difference.
      I realize that these groups are far from bughole perfect, but I believe the point was illustrated well.

    • #24162
      IllinoisCoyoteHunter
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      Very interesting. For the average reloader with just a reloading press I am wondering if you could make a punch and die that does the flattening? I know the tip of the punch being as square as you got yours to the check may not be as precise, but I think any little bit would help. I bet annealing first might help a bit too??

      Maybe I spoke too soon…lol

    • #24165
      Goodsteel
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      Spinning the check while uniforming is key. Forming with a punch is how they were made in the first place. The trick here is to get these puppies dialed down to a couple TEN-THOUSANDTHS of an inch.
      The XCB team has tested this thoroughly. A simple drill press is all that is required.

    • #24169
      IllinoisCoyoteHunter
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      Sounds like you got it figured out. I’d be interested to see if the TIR on the check changes after being crimped on the bullet.

      I am glad to see cast bullet shooting being taken to the next level. Excellent work!

    • #24183
      Goodsteel
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      IllinoisCoyoteHunter;n2312 wrote: Sounds like you got it figured out. I’d be interested to see if the TIR on the check changes after being crimped on the bullet.

      I am glad to see cast bullet shooting being taken to the next level. Excellent work!

      Only if you did a lousy job cutting your sprue. If your bases are flat and beautiful, then the installed check mirrors that precision.

    • #24211
      Newt
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      Wish I had one of those gizmos to use with 22 caliber checks. I’ve noticed the cupping also but didn’t know how much they are deformed by the initial pressures so I haven’t pursued trying to uniform them. Seems it would be worth a try though.

    • #24220
      Smoke4320
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      So now your trying to sell me the MBT GC-FUST (Gas Check Flattening, Uniforming, Sanding Tool)
      Oh the inhumanity of it all 🙂 🙂
      Actually It shows just like my 1000 yds comp days everything you can make consistent and true the better to groups
      I still apply lots of those techniques learned there to cast bullet shooting

    • #24247
      Goodsteel
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      Smoke4320;n2369 wrote: So now your trying to sell me the MBT GC-FUST (Gas Check Flattening, Uniforming, Sanding Tool)
      Oh the inhumanity of it all 🙂 🙂
      Actually It shows just like my 1000 yds comp days everything you can make consistent and true the better to groups
      I still apply lots of those techniques learned there to cast bullet shooting

      If I was trying to make a sale, I wouldn’t have shown how to make them! LOL!
      Yes, everything matters, but things pertaining to the rear end of the bullet matter most of all, and I don’t think there’s very many who would offer much of an argument to that statement.

    • #24250
      Smoke4320
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      I was just injecting some humor in the post.. No offence meant
      besides I am tool man thru and thru ..

    • #24251
      Goodsteel
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      SwedeNelson used a pin gauge set. Just grabbed the right size pin and chucked it in the drill press. I thought that was pretty smart!

    • #24254
      Smoke4320
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      Now theres a great Idea.. DUH.. a pin gauge set

    • #24264
      Goodsteel
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      Yeah, I mean it’s kind of hard on the pins, but a little egg-spearmint-nation would tell you what size is the correct one, then you just buy the precision pin on flea-bay for a couple bucks. This doesn’t have to be dramatic at all.
      Also, you don’t need a certified granite slab like I used either. Just zip on over to your local granite countertop place and ask for a piece of scrap.
      Now the double back tape is a tough one. I don’t think you have any choice but to buy the stuff at full price. LOL!

    • #24271
      Fishman
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      Pretty neat stuff Goodsteel. I’m not to the point of precision cast shooting yet, but it’s cool to see others making a path.

    • #24315
      Anonymous
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      Nice work Tim. Now I have another project to play with. The fun just never ends. Got some treatable drill rod that should fill the bill.

    • #24440
      Doc Highwall
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      Tim, could you post a picture of your gas check seating tool?

    • #24444
      Goodsteel
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      No, I didn’t take any pictures. Bjornb has one of the tools I made and it helped a little.
      After discovering this method, I have done away with all my various attempts to get GC’s seated squarely. One looked like a die that goes in the 450, with a perfect impression turned in the center. Another was milled into the top of my machine vice so a nose punch could be mounted in the chuck. Another was a rod that went through the PT sizing die with a nose profile turned in the tip of it so the bullet could be inserted into the die in the normal way and seated firmly into the check with the nose punch from above.
      Anything I tried kept pointing back to the fact that I’m trying to use the bullet to flatten the gas check.

      There was a moment when I looked up and asked myself “what are ya stoopid? Fix the check first and THEN put it on the bullet”.
      So I scrapped my tools and went in a new direction. Felt like I was attacking the problem at its root.

    • #24463
      Doc Highwall
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      Thanks for the reply Tim.

    • #24473
      IllinoisCoyoteHunter
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      So are you still using the gas check seating tool after you true up the checks?

    • #24479
      gnoahhh
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      I solved that problem too, but I came at it from a different angle, and stopped short of where you took it to.

      For years I was plagued by Hornady checks not fitting well onto an old custom .30 mold from Saeco. The bullets as they come from the mold have a tapered shank, and when a Hornady GC is seated, the leading edge of the check pushes lead and comes to a grinding halt shy of seating fully. For years I put up with it and suffered enough fliers that I by-and-large neglected using the mold very much. Then a light bulb went off in my head. I turned a punch with a shank that matched the tapered shank of the bullet, out of CRS and case hardened it with Kasenit. My little dentistry prosthetic arbor press has a receptacle in the ram into which I affix the punch. Pressing the punch into a GC against a polished steel anvil re-forms the GC into one with tapered walls and flattens the “hump” at the same time. Eureka! The checks now fit perfectly snug, and a pass through the sizer locks it into place. Average group sizes shrank decently, but more importantly the fliers have decreased dramatically.

      I made it out of CRS and case hardened it because I figured I didn’t want to waste a chunk of tool steel if it didn’t work out. Now, after re-forming thousands of checks, I can’t discern any wear so I probably won’t mess with it. (Probably due to the wonderful old formula Kasenit I have– several cans of the stuff I rescued from my Gramp’s shop a long time ago.)

      After reading this treatise, I may expand on my setup and take it to the next step of spinning against a polished steel anvil either in the Bridgeport or drill press. (It seems so overkill to do it in the Bridgeport though!)

    • #24481
      Goodsteel
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      IllinoisCoyoteHunter;n2673 wrote: So are you still using the gas check seating tool after you true up the checks?

      Quote from post #3 earlier in this thread:

      Finally, I tried them on the Linotype bullets and was pleased to find that I could push them all the way to seated depth with my thumb, and the resistance was superb. Checking the bases for squareness revealed that I attained better accuracy using this method than I ever was able to do with the best seating devices I have ever created.

      No, I do not use them. Either the GC goes on easily with thumb pressure for a perfect snap fit on the base of the bullet, or it needs to be uniformed with a larger mandrel.
      Pressing on the bullets damages them far worse than any base perfection can overcome in my opinion. I have no proof of that, but my philosophy is that I want the trip down the barrel to be the harshest thing that bullet ever encounters. Up till then, the entire shop bows to it’s wishes, and it’s carried around on a velvet pillow so to speak.

    • #24483
      Goodsteel
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      OK, first of all, shoot those puppies at 2750FPS and tell me what you get. LOL!
      Secondly, cast bullets is all about using what you have to get the job done. I have no drill press, so I just had to make do with the 3700lb milling machine. Har!

    • #24613
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      Very interesting and informative. I would also be interested in uniforming 22 cal checks. Something to try when I retire.

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