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Post by wfa on Jun 13, 2015 15:39:27 GMT -8
The "big question" is what happens if I tailor the load to the flash hole, I.E., drop the "large" flash hole load back to the same velocity of the "small". As I said, the difference in accuracy, if any, is very slight. I really don't want to "wear this subject out", but the 264 LBC is an interesting round to experiment with because it's economical on powder, and recoil is very minimal. Even the "bad" loads are "accurate". IIRC, the worst group I've shot was under 1.5 MOA, using a 4X scope, light profile barrel, 7# rifle. That's hard to beat!
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Post by GLSHOOTER on Jun 13, 2015 15:48:33 GMT -8
The "big question" is what happens if I tailor the load to the flash hole, I.E., drop the "large" flash hole load back to the same velocity of the "small". As I said, the difference in accuracy, if any, is very slight. I really don't want to "wear this subject out", but the 264 LBC is an interesting round to experiment with because it's economical on powder, and recoil is very minimal. Even the "bad" loads are "accurate". IIRC, the worst group I've shot was under 1.5 MOA, using a 4X scope, light profile barrel, 7# rifle. That's hard to beat! It's all about the smooth. Less violence on powder ignition with better burning progression is the key IMHO. We know that for a fact velocity is not the main factor in accuracy. If it were we'd all dial a 168 grain 308 bullet for 2650 like a FGMM and be happy. I wish it were that easy. No doubt the 264 is an inherently accurate round. It may be the best in the stable. Well except for the 243 LBC and the 20 Practical that is.....  Greg |
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Post by wfa on Jun 13, 2015 16:47:38 GMT -8
Understood, but it's about barrel vibration, too, especially with a light profile barrel. As I understand it, vibration is a function of pressure (and, yes, the pressure curve); velocity is all about pressure (and again the pressure curve). IMO, there is a correlation, at least for any given barrel.
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Post by GLSHOOTER on Jun 13, 2015 18:39:46 GMT -8
Yep. It's all about vibrations.
Greg
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Post by wfa on Jun 14, 2015 8:52:33 GMT -8
Well, I think I've just proven that I can't prove anything given my equipment, skill, and budget.
I reduced the load cited previously to 28.8gr 8208. The results for 10 shots each:
"Larg(er)" flash hole:
Hi: 2534
Lo: 2487
Avg: 2513
ES: 47
SD: 13
"Small" flash hole:
Hi: 2549
Lo: 2510
Avg: 2526
ES: 39
SD: 13
For all practical purposes, the ballistics are identical.
Today, the "large hole" group was smaller than the "small hole" group; also notice that the velocity is slightly higher for the "small hole" - the exact opposite from yesterday. Weather conditions were nearly identical - 90F, 53%.
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maxbc
Junior Member
Posts: 10 
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Post by maxbc on Jul 23, 2015 16:27:40 GMT -8
Sinclair makes a decapping die that accepts either large or small pins. It is reasonably priced at around $20 and pins are about $7.
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Post by GLSHOOTER on Jul 23, 2015 16:46:48 GMT -8
Sinclair makes a decapping die that accepts either large or small pins. It is reasonably priced at around $20 and pins are about $7. They sehd both 0.80 and 0.60 pins. That's a good deal. I just use my Redding PPC decapping assembly in all my variants or the old pin and hammer decapping set up like the BR guys. Greg |
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