March 10, 2018 at 5:37 pm #49655Larry GibsonParticipant
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As I’m typing this I have to admit I dd not expect to get the results I did. Shooting cast bullets at 600 yards is a long shot. Getting the results I got was truly amazing. We have all gone out and defied the odds and shot some pretty small groups once. But to do small cast bullet groups, especially when they run 2900 fps, consistently means the rifle, load and the bullets are good, very good actually. I wish to thank Tim (goodsteel) for the excellent precision work he did rebarreling my M98 action and the custom touches he does. His work is truly precision at it’s best. The resulting accuracy at 600 yards you’ll see in these tests at 600 yards verify that.
The rifle I used (rebarreled and tricked out M98 action by Tim) is named Dawn. If you been following my HV cast bullet testing over the last 3 years you’ll see I’ve mentioned her often. I named her as she was the “dawn” of a new era of HV cast bullet shooting. I was shortly asked what acronym it stood for, I thought Disgruntled Antagonists Worst Nightmare fit. If you are “offended” by that then you need only to stop reading on this forum and go back to your own…..’nough said.
Back to HV 30 XCB cast bullet performance at 600 yards;
The weather cooperated with a beautiful morning here in Arizona. Was at my shooting place in the desert at daybreak and got set up so 1st shot went down range at 0730. Temperature was 45 degrees and when I finished shooting at 1030 it was up to 60 degrees. The humidity was 25%. I staked the target (older NRA “B” target for 600 yard) on the hillside and put up the wind flag. The wind was very calm to begin with so I was able to get off 4 groups (three 10 shot and one 15 shot) before it got squirrelly. Even at the 2900 fps I’m shooting the 30 XCB at out of my 30×60 XCB rifle given the low BC the wind really pushes the bullet around at long range.
Off to the right of the target a couple feet you can see a little black rock in the road. That’s my “spotter” target. About 2/3 the way to the flag pole is a couple large powder jugs filled with water, more on them in a bit. Repairing back to the 600 yard firing point I prepared a prone shooting position. From the rifle the target looked like this;
[can’t get the picture turned right?)
I took 6 shots (3 foulers and then 3 confirm) to get “on” the sighter rock and then I put 3 rounds into the black powder jugs of water. I should have quit then and rebuilt my shooting position as I had just set the front rest on the bare rocks/gravel. That didn’t work well during the next 10 shots on the target as the feet of the rest dug into the ground. I knew I had dropped on down out of the group as the rest was not solid at all so I called that shot. I then went up and checked the target…….sure enough there was a shot down and away. Here is the target. The 9 shots that were “good calls”, even with the unsettling rest, went into right at a 10” group.
The ballistics from the “Applied Ballistics” program said 20.28 moa elevation correction was required to go from a 100 zero to a 600 yard zero. I had thus set the elevation on the Leupold 6.5×20 scope (zeroed at 100 yards) up 20 ¼ moa, looked good to me and was confirmed with the sighters taken on the “sighter rock”. However, I obviously need to go right ¾ moa for windage. The tears in the target are from rock splatter shooting at the “sighter” rock.
I pasted the bullet holes and tears and repaired back to the 600 yard point and rebuilt my prone position using a slab of plywood for the rest. Don’t know why I just didn’t do that in the 1st place…..
It was a much more sold rest and position as the next group demonstrates. I adjusted the windage ¾ moa right…..should have gone 1 ¼ moa right but what the hey…..can’t complain. The 10 shot group is just under 7”. Had to say I was duly impressed!
I pasted those holes and wet back to the 600 yard point. I was waiting long enough between the groups so the barrel would cool. The third group was interesting because I had given the windage another ½ moa right and shot 3 “sighters” on the sighter rock and all appeared good. As I settled in on the target the wind flag began to move. I could not feel any wind movement where I was but it appeared a 1 -2 mph wind had picked up coming out of 10 o’clock. I just held steady and shot when the flag was in the same position (condition). In that small of a wind the group moved 2 moa right or about 12”. In watching the wind change I lost count of the number of shots I had fired…did I shoot 9 or did I shoot 10? So I shot another one just to be sure….turns out I shot The 11 shot group size was a tudge less than 6”…..that’s moa accuracy at 600 yards!
Again I pasted the holes and returned to the 600 yard point. I had 15 shots left and the wind was getting squirrelly now coming in 11 o’clock and switching back and for the to 1o’clock. I left the zero alone and shot the 15 rounds on target w/o shooting any at the “sighter rock”. Just shot the 15 straight away. Looking at the target I should have given it a half moa more elevation because the head wind caused the bullet to slow down quicker with more drop. You can see the lateral dispersion also due to wind. Since this was the 1st time I had shot the 30 XCB at such a distance it as a learning experience seeing what the different effects the wind had on the bullet. Even so I was very pleased with a 9” group with the 15 shots.
All that took about 3 hours to shoot the 4 groups. By then, 10:30 am it was 60 degrees and the wind was still switching back and forth. I took 10 shots at the sighter with my suppressed .308W M70 with a M118 White box duplication load (LC Match cases, WLR primers, 41.5 gr IMR4895 and a 174 gr M118 bullet. I hit the sighter rock 6 times. I then shot a few rounds out of my Ruger OM Vaquero 44-40 at a couple pop cans. The morning had gone well.
Oh, almost forgot the powder jugs with water. I had set them tandem so the 30 XCBs would have to go through both. The right bullet was the 1st hit, then the left and finally the center shot. The jugs noticeably jumped when hit, especially the first hit. Here is the front of the 1st jug;
All three hits went through and through. Here is the back of the rear jug and you can see the 1st bullet tumbled in the 2nd jug and the hydrostatic shock burst the side of the jug.
So that ended a very good morning with the average moa of the two 10 shot groups, the 11 shot group and the 15 shot group 946 rounds total) was 1.3 moa. ……not too shabby accuracy for a cast bullet at truly HV at 600 yards……..
March 13, 2018 at 2:54 pm #49691GoodsteelKeymaster
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And that friends is how you make cast bullet history.
I don’t recall ever having seen anyone do this with a 30 caliber rifle shooting cast bullets (at least not having documented the results so well/IE: most folks can’t even BS about 1.3MOA at 600 yards with cast because no one would believe them!). All respect Larry. Thanks for posting!!!!
March 13, 2018 at 6:26 pm #49695Larry GibsonParticipant
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Quite frankly I was expecting 2 moa or perhaps 2 1/2 moa simply because of the long range. To say I was surprised by the actual precision of the groups (not just one but 4) would be an understatement. Over the past 10 years working with fast, medium and slow twist .30 caliber barrels shooting cast bullets at high velocity (2200 to 3000+ fps has been a revelation if not a revolution. The work you, Bjorn and others did along the way was a great asset. Discovering the nature of what design parameters were needed for a high velocity cast bullet using several “standard” designs led us to the break through NOE 30 XCB design.
Recent testing at 500 yards with a 10″ twist demonstrated right about 2 moa was accuracy was possible at that distance even when pushing the RPM threshold up at 2267 fps. In the 14″ twist at 2600 fps we found 1.5 moa was indeed possible. Our concept of keeping the RPM controlled has led us to this level of success at 600 yards by using a 16″ twist barrel, using a cartridge with sufficient capacity for 100% load density with a slow burning powder, using the the 30 XCB bullet cast of #2 alloy, properly weight sorted, GCs properly put on, an excellent lube such as 2500+ thus pushed to 2900 fps has controlled the RPM. What we have done with the 30 XCB bullet shot from Dawn at 2900 fps is give the bullet about the same RPM as a bullet from a 10″ twist rifle at 1800 fps would have…….right at 130,000 RPM.
It has been claimed we post “negativity” by telling folks they aren’t going to accomplish this level accuracy at this level of velocity (2600 – 2900+ fps) with cast bullets out of “grandpa’s M70 30-06. Fact is, we do tell them that, but it is not negativity…..it is the truth.
You can shoot cast bullets at true high velocity with amazing accuracy at long range……you just have to do it correctly.
March 13, 2018 at 7:20 pm #49696slim1836Participant
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Truly good research and testing, not to mention a very good bullet design. Thanks for sharing your hard work, it’s appreciated.
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