Interesting Sizing Comparison

[Texas by God]

An interesting start to what might be an informed challenge to some long-standing dogma about the "correct" size for best performance.

I challenge the suggestion that "eccentricity" is as important as stated. I made up some cast bullets and severely deformed the nose portion using side-cutters and a belt sander, and their accuracy seemed undiminished at 100 and 200 yds. Not scientific, but others have seen the same, so long as the base of the bullet is not deformed.

I learned this by modifying fmj 8mm ammo as a kid. The side cutter deformed bullets shot as well as the carefully filed ones.
My .358 Win shot so good with .358" boolits there was no reason to deviate. The same for my 30-30 bolt action except I use .309"- I tried .311" and went running back to .309". Slugging the bore is important because it is information- whether you use it or not is up to you.

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[#40Fan]

OP, here.

I didn't think I'd get even the little bit of attention on this post as I have and might have ruined what could have been a good possible test of these bullets.

First off, I only had a limited supply, so 5 shot groups seemed worthy enough. I did fire them in order from smallest to largest. These were all subsonic with about 5 minutes between each group. I doubt barrel heat would have had an effect. I shot jacketed bullets right afterwards and they shot just as well as they have before.

What I did wrong with the remaining GC'd and PC'd bullets that I had left.... I resized them all to .308", but I didn't keep them separated (.309" to .308" in one group/.310" to .308" in another group). Then to make this whole test even worse, I tried half of them with a different powder that showed promise with my PC'd bullets. Needless to say, I didn't get the grouping I had before. I'll just call it like I see it and it was a waste of time and a failure on my part.

I am now left with 20 GC'd and un-PC'd bullets. The last of the bullets sent to me by Mustang. 10 of them are going to be sized to .308", PC'd and then sized again to .308" and shot as a 10 shot group with the original powder used in the first test. What should I do with the remaining 10? I only have a .308" and .309" sizing die.

[HangFireW8]

An interesting start to what might be an informed challenge to some long-standing dogma about the "correct" size for best performance.

I challenge the suggestion that "eccentricity" is as important as stated. I made up some cast bullets and severely deformed the nose portion using side-cutters and a belt sander, and their accuracy seemed undiminished at 100 and 200 yds. Not scientific, but others have seen the same, so long as the base of the bullet is not deformed.

Nose deformities, in jacketed and cast, have long been known to have less effect on accuracy than other defects. There have been scientific tests of this- drilling holes off-center in the bases of otherwise good jacketed bullets, for one example. Truing noses of Sierra HPBTM bullets versus untrued for another. But I have to repeat that most group shooters here won't notice the difference of a eccentrically sized boolit in the overall size of their group. Case/neck eccentricity is more likely to be a measurable factor, but again only if already accurate enough to notice.

I plan on repeating with cast some of experiments using I did years ago with jacketed, but due to family commitments my progress is always glacial. I will put the cast results up here when I have them, but don't hold your breath.