Re: 210 bergers blowing up?? help 30-378 wby
Roy, back when the 7mmRUM was a not-yet-released thing, I decided to wildcat it. I liked the idea of Berger's .284" 180VLD at RUM velocities, so I called Walt Berger. Walt asked about the twist & expected velocity. I heard him say, "Wait a minute, I think I have some of the data from the 6.5mm project around here somewhere...." Several minutes later, he get back on the phone, did some calculations, & said "Yep, that's awful close. They may come apart, and they may not." He explained exactly what was posted above - super high RPMs & the thin J-4 jacket aren't real conducive to rough throats or sharp rifling.
Being a true gentleman, he recommended I speak to Jimmie Knox &/or Bob Cauterucio since both used Sierra-thickness jackets in their bullets. Both fellas also proved to be wise, fine, patient gents & helped out a loony nobody with a theory. The rest isn't exactly history, but a Cauterucio 156 or 176 will definitely hold up to RUM speed. I still shoot Berger 70s & 80s in .223, as much for loyalty to good people as the quality they hold.
I was spotting for a buddy in an F-class match a couple of years ago. He was shooting a 22-250AI & some J-4 jacketed bullets. All was going well - 10, X, X, X, 10.... then POOOF about 200 yards out. I was on the scope & saw it happen. The guy spotting to my left saw it happen also, looked over with a smile, and motioned to my pal to say, "Does he know?" I shook my head (sadistically) & waited. John finally looked over & said, "Call for a mark!" I told him I would, but he wouldn't like the result, because what was LEFT of his bullet was somewhere between us & the 300 yard line. [img]/ubbthreads/images/graemlins/grin.gif[/img]
Sorry for the long post, but I figured from the tone of your post you could use a little humor, plus a reminder that whatever mistakes we make along the way, rest assured some other shooter(s) has done the same. [img]/ubbthreads/images/graemlins/wink.gif[/img]