I can give it a shot with my Mitutoyo’s.
I bet you’re correct. It doesn’t make sense that 4 cases all look the same (just like your picture) because there couldn’t be enough metal lost from the firing pin to leave that much metal in every primer. It would be too short to even make it through the bolt orifice. Is that from a pierced primer?
These were shot a few months ago. About 50-60 rds in on a new McGowan barrel. Maybe 60F max but likely colder as it’s winter in VA. Similar to other rounds. Same load and Lapua brass. Also tried new Alpha srp 25CM specific brass. Similar result without the metal sticking out. Deep craters though
Did it again today and it was 83F 57% humidity. To reiterate the same BCG/bolt, now a new firing pin, works fine with .308 SP10 upper and 8.6 BLK SP10 upper (super and subs). I hope someone can shed some light on this.
I did adjust the block down and feel like it didn’t cycle. Also made various open adjustments until cycling suppressed but honestly don’t remember if it affected the primers. It does occur unsuppressed also. The thing is, this gun ran fine without this happening for 50 or so rounds. I didn’t change powder or other variables. I did change firing pins because the original got chewed up at the tip from this process. There’s a pic above of that I believe. Just very strange and I figured surely someone on here would have the answer. I appreciate the tips and may have to change primer. Just doesn’t make sense how it started suddenly
Ahhh. I did get a new BCG from Seekins and I bet I didn’t put the original JP HP bolt in that carrier. That’s been a while ago but who know. I’ll look. Thanks
0.0580” at the tip. It’s got some carbon fouling although I wiped it down. Maybe that’s the 0.008”
I did not.
me neither, thought I'd seen it all tooDamn, I didn’t even know that could happen…..
I found the order in my email from 2021. It is a JP enhanced bolt and not HP Enhanced. I didn’t realize at the time. Thanks. I’ll start there by getting a proper one and proper JP HP enhanced pin. Also, several engineers at Federal are stumped and said they’ve never seen the anvil come through like this. They have requested the used cases and old titanium V7 pin to evaluate. I thought that was pretty nice of them.
I’ve got a Tubbs flat spring and 5.6oz KAK wt. There is no “forward assist” on the Seekins SP10. I can manually assist by pushing forward on the side of the bcg though. I’ll try that before swapping the bolt into the old Seekins carrier. Thanks
Some loads got too hot initially, 42.0 of H4350 and Berger 133. I scaled back to 40.0 and still got pierced primers until changing to the high pressure bolt and different Seekins carrier. Now this happened. Not sure it matters but for what it’s worth this new carrier has 3 gas ports and prior that I used with the non-high pressure JP bolt had 2. Seekins rep says they’ve used a few different carriers over time.
So, this was the issue. Noticed the carrier not al the way forward and I could physically move it back and forth 1/8” or so.
Thanks for the info. It’s almost certainly the 2.5” KVP 5.6 oz buffer in an A2 rifle tube. For carbine I see now.
