02-10-2021, 01:53 AM
StoneHendge Wrote:I'm guessing at this point that it was the bullets. Barrel had been almost exclusively fed a diet of 123 grain Scenars. I measured a bunch and they are all .2625 diameter. As are all of the other 6.5 bullets I have on hand: 140 gr RDFs, 90 gr TNTs and the 85 gr Sierra Varminters. Barrel has always gotten max speeds (and pressures) 0.6-0.8 gr below what others report, so I'm guessing it's a little "tight".
Measured about 100 of the Hornady FMJs. All were .2630 except for 3. Which were .2635. My only thought at this point is that I got a pressure spike sending a fat one down the tube.....
Try to save a few bucks and buy cheap bullets, trash a $130 bolt.
SH:
I don't think it was the bullets. I think it had something to do with using 7.62 X 39 brass. I too used Fed 210M primers in my fireformed brass and didn't notice anything weird for the most part but then I would get exceptions of blown primers and high pressures. One thing is that I always got donuts to various degrees when I fireformed 7.62 X 39 brass into Grendel. Some were pretty severe and others not so much but most of the brass had them. I started to internal ream the brass after fireforming and the first shot. What a PITA. No -- I don't think it was the bullets you are using. I got a feeling it has something to do with the brass and large primer.
LR55