6gt
- Thread starter Dthomas3523
- Start date
Could be caused by your headspace, if it’s just an ejector mark, unaccompanied by heavy bolt lift. Cases growing .008 means your headspace is prolly something like .006-.007 over a go gauge, which is fine (cause you’re only going to bump .002-.003 back from that), but leaves enough room for the case to get a running start at the bolt face and leave a mark from the ejector.
Alpha brass is 001 under my go gauge. If it's growing 008, and prob not fully formed due to first firing, likely 009 for true headspace, that chambers out of spec, however it's workable. You'll be fine future firings, I'd strip your bolt down and just bump enough for free bolt fall.
I had mine chambered 002 past go, get 003 growth on virgin. Bumping 001 over virgin. Once you get to the point of needing a new barrel, you could run into a situation with your brass........if the smith cuts the barrel proper, you'll need to bump all your brass back quite a ways. Or you can send him one your sized cases and tell him to use it as a go gauge but 002 deeper. However, that chamber will once again be out of spec.
I had mine chambered 002 past go, get 003 growth on virgin. Bumping 001 over virgin. Once you get to the point of needing a new barrel, you could run into a situation with your brass........if the smith cuts the barrel proper, you'll need to bump all your brass back quite a ways. Or you can send him one your sized cases and tell him to use it as a go gauge but 002 deeper. However, that chamber will once again be out of spec.
He’s still within spec, though, technically - SAAMI allows .010 for chamber dimensions (1.3607-1.3707 at the datum). Shorter headspace is arguably a little better, but once his brass matches his chamber, he’s good to go. Probably goodness not running hotter stuff, though - Hornady factory stuff might show more issues, especially with the tight bore and longer headspace.
You’re spot on about having the smith who cuts the next barrel match fired brass minus a couple thousandths, just to save brass wear.
My jgs gauges in gt and creed are 005 apart, go VS no-go. 007-008 seems excessive.
Sounds like your cases are stretching a fucking lot. 8 thou ain’t nothing lol.
That said, 32gn of Varget or 36gn of H4350 sounds about right and shouldn’t blow shit up.
It takes 2-3 firings to really fire form brass… I’d just stay on the lower end of charges until your brass settles in before you push it.
That said, 32gn of Varget or 36gn of H4350 sounds about right and shouldn’t blow shit up.
It takes 2-3 firings to really fire form brass… I’d just stay on the lower end of charges until your brass settles in before you push it.
