Re: 22 cal 90gr Bergers at 3100fps
Wild Bill, reeldoc and cheyenne,
Thanks for helping out with Steve's questions. I always do my best to give truthful and complete answers based on my experience and feedback from others, but clearly I don't know it all!
These long bullets are particularly difficult to make universal statements about, they're just so finicky. I spoke with a shooter last week who was disappointed that he could only get 3100-3200 from a 1:7" twist 22-.284 before the bullets blew up. The fact that cheyenne is able to get them to 3500 and their stable from a 1:8" twist is a surprise for me (not that I doubt it).
Bullet failure and 'max attainable velocity' has a lot to do with the condition (roughness) of the bore. The shooter with the .22-284 probably had a rougher barrel. This, in addition to the 1:7" twist probably combined to make the bullets less survivable than cheyenne's rifle, which probably has a smoother barrel (and a 1:8" twist). This line of thought begs the question: how long will cheyennes barrel stay smooth enough to keep from failing them at 3500? I may be wrong, but I suspect that it may not be many 100's of rounds before the barrel becomes rough enough to start failing the bullets.
Regarding thick vs thin jackets; of course the thicks will stand higher velocities than the thins. It's difficult to say precisely how much though; the roughness of the bore will still be an important factor.
Thanks again for sharing your experiences. We're all in this to learn.
Take care,
-Bryan