Gunsmithing Bolt closes hard on go guage
- Thread starter Schw15
- Start date
Fixed shoulder. I've put some barrel nut barrels on closing hard on go guage and I was fine and didn't worry but since this isn't my barrel I wanted to see everyone's thoughts. Besides adjusting dies any concerns
Ok have you tried a new piece of brass to see if it will chamber?
Belted cases headspace on the belt not on the shoulder so the tight headspace will not affect case capacity, after a case is fireformed to the chamber you typically treat it like a standard (non belted case) and just push the shoulder back as usual.
Provided the chamber was cut correctly you should not have any issues.
Personally I like to use factory ammo to test a new barrel, not that I have any reservations about my handloads
but should there be an issue I can rule out me.
What caliber?
Provided the chamber was cut correctly you should not have any issues.
Personally I like to use factory ammo to test a new barrel, not that I have any reservations about my handloads
but should there be an issue I can rule out me.
What caliber?
7mm-300 win mag. I've ran them for awhile now and I've ran one with tight chamber but just was asking to double check what I told him since it's his not mine lol yes exactly what I do fireform to chamber and bump back .2 and works great
I reload for a old 22 savage high power round that headspaces on the rim. Upon firing, factory ammo will have the shoulder
pushed forward somewhere in the .020- .025 range depending on the MFG. On initial firing I use an o-ring slid down the case to the rim to keep the case head tight against the breech bolt to minimize case stretch.
Your tight belt headspace is helping you with case stretch but generally belted cases are a PITA.
Peterson makes .300 Win Long that keeps shoulder farther forward. I am loading some now and it’s good quality stuff.
Unless its the 300 Win Mag Long cases from Peterson Cartridge Company.
They matched the shoulder to headspace like a non belted, so it’s pretty damn close on standard chamber. I’d guess it’s still a few thousandths off just to make sure it fits in most since it’s main purpose is to reduce stretch and premature head separation.
20 or so years ago I did a Nesika bench/varmint rig for a guy in 6mm-284. The absolute best of everything and if you were shooting for shit, you wouldn't get a wiff. It was a complete turd. (as in minute of Pringles can lid off a rest inside a tunnel) I put close to 200 rounds through that thing thinking my loads were goofed.
The guy who hung the barrel threw a Go Gauge in it and noticed the bolt had just a "pinch" on closing. "So f@cking what" was my response as I had a serious case of the ass over it. He squeaked the chamber with a ream to loosen it up a smidge and I called him an idiot for it. Then I went into the tunnel and learned (once again) just how ignorant I truly am. The thing INSTANTLY started shooting in the .1's. The results were absurd.
One of the hardest-hitting rifles I've ever done still to this day along with a very valuable lesson. H/S values exist for a reason and it's been my experience that the looser side of the tolerance isn't as bad as some might try to make it out to be. So long as your close enough to not start sneezing case heads or "muffin top" the things you're fine.
C.
^^^
Interesting, but methinks this would more likely have been due to the case being "tight" in the chamber against the boltface.
If the shoulder datum is bumped back a few thou with a sizing die, giving the same "headspace clearance"/relative fitment as if both chamber and brass were precisely to spec- I don't see how it could matter?
Interesting, but methinks this would more likely have been due to the case being "tight" in the chamber against the boltface.
If the shoulder datum is bumped back a few thou with a sizing die, giving the same "headspace clearance"/relative fitment as if both chamber and brass were precisely to spec- I don't see how it could matter?
It’s belted headspace so shoulder shouldn’t be in the conversation but OP can advise.
So i was just asking I'd you guys ever seen anything negative from closing hard like more pressure. But it being belted magnum the shoulders come almost 10 to short. Once fired formed be able to bump back 2 and should be good. The only other issue is not being able to resize enough but that's when trimming shell holder or bottom of die
In a 6.5 Creedmoor, for example, the head space on the case has a .007" window (SAAMI), the top end of that window being identical to the bottom end of the chamber headspace window. So MOST of the time you're not going to have any interference with a GO, or GO -.001-.002, but it depends on the case/ammo mfg. and how that particular lot of cases was produced. If you're reloading, the issue is non-existent after the first firing because you simply bump the shoulder by screwing the die down (if you get crazy, may need to grind shell holder or die to get more bump).
In short, though, there's no real safety concern with short headspace, just the possibility of function issues.
In short, though, there's no real safety concern with short headspace, just the possibility of function issues.
You think the headspace was causing accuracy issues? With brass sized from that chamber? Do you believe this was from the sizing die not matching the chamber, or for another reason? Is it possible the chamber or mounting had another issue? This is an interesting case.
Thanks
This was all done with a new 6.5-284 brass squished down to 6mm. The only thing we saw prior to the reamer squeak was some burnishing on the case head and the shoulder. -it was pretty conclusive that the chamber was just a smidge tight. Like I said, "Knucklehead" literally just went in by hand and gave the chamber a quick squeak with the tool, then we followed up with a polish. I can't imagine it changed the HS by more than one or two .001's. It was just enough to take the load off the bolt lugs when rolling into battery.
Why it worked I really have no idea. When fire forming cases such as an Ackley, PPC's, Comp Match, etc... I always do the false shoulder trick rather than relying on a long seated bullet to hold the case against the bolt face. It always results in a firm "pinch" as the bolt is rolled into the closed position. It works there in every instance while avoiding the accuracy issue I experienced in this particular case.
Why this one was different is something I've wondered about off/on over the last two decades but I've never had the ambition to try and replicate it to see what the cause is.
