headspace
- Thread starter af_newbie
- Start date
- Location
- Somewhere on the Hudson Bay Coast
You would need to shorten the barrel from the end that threads into the action, then re-thread the barrel and re-cut the chamber. Pretty much a gunsmith gig.
What do you hope to accomplish? If the exercise is to simply extend the life of your brass, it could be at the cost of reliable functioning, but if the purpose is to improve accuracy you might be better investing in a match grade barrel.
What do you hope to accomplish? If the exercise is to simply extend the life of your brass, it could be at the cost of reliable functioning, but if the purpose is to improve accuracy you might be better investing in a match grade barrel.
Ishootguns
Regular
- Location
- Acton Ontario
Easiest way is to buy a USGI bolt. The lugs are a little larger and will tighten things up considerably.
I'm kinda worrying that using commercial 308 ammo might cause
problems since the headspace is above 308 FIELD (1.6380").
I have another rifle with headspace 1.6400" and I've been using it to
fire commercial ammo, but I'm not sure if it is safe to do this.
Anybody know if a slightly longer headspace (by 0.002") than 308 FIELD
caused any problems in the real world?
I was thinking about the possibilities of getting a norc bolt hard chromed to reduce headspace. If the plating was .003" thick it would reduce headspace .006" (stackup? from chrome plating on the back of the lugs and the boltface) but I dont know if it is viable. I have seen chromed m-14s but do they still work?
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Some comments:
Setting the barrel back one turn and rechambering is problematic for two reasons: the chamber is chromed, and a carbide reamer would be needed to cut it, and the gas system would have to be altered because the gas port, cylinder, etc. would be 0.1000" closer to the receiver.
Can't say if plating would be a viable option.
Swapping in a USGI bolt might help. As far as that goes, swapping in a different Chinese bolt could make a difference, too. Selective assembly, who knows?
Now, consider headspace gauges:
Saami MilSpec.
Go: 1.6300 1.6350
NoGo: 1,6340 1.6405
Field: 1.6380 1.6455
You report that your rifle will accept a 1.6390 gauge. That is 0.001" over Saami Field. It is less than NoGo by military standards. Your rifle is correct for milspec. ball. Shoot milspec, and be happy.
If you want sporting ammunition, and are uneasy shooting factory, handload. You could even send three fired cases to Huntingdon Die Specialties and get a custom FL die, to produce cases sized exactly correctly for your rifle. Or, you could just back out a standard sizing die and custom size the brass for this rifle. Just size it enough that free chambering is achieved, without setting the case back all the way to the beginning. SIze mil. brass like this, and you should have good hunting ammunition set up just right for your rifle.
Setting the barrel back one turn and rechambering is problematic for two reasons: the chamber is chromed, and a carbide reamer would be needed to cut it, and the gas system would have to be altered because the gas port, cylinder, etc. would be 0.1000" closer to the receiver.
Can't say if plating would be a viable option.
Swapping in a USGI bolt might help. As far as that goes, swapping in a different Chinese bolt could make a difference, too. Selective assembly, who knows?
Now, consider headspace gauges:
Saami MilSpec.
Go: 1.6300 1.6350
NoGo: 1,6340 1.6405
Field: 1.6380 1.6455
You report that your rifle will accept a 1.6390 gauge. That is 0.001" over Saami Field. It is less than NoGo by military standards. Your rifle is correct for milspec. ball. Shoot milspec, and be happy.
If you want sporting ammunition, and are uneasy shooting factory, handload. You could even send three fired cases to Huntingdon Die Specialties and get a custom FL die, to produce cases sized exactly correctly for your rifle. Or, you could just back out a standard sizing die and custom size the brass for this rifle. Just size it enough that free chambering is achieved, without setting the case back all the way to the beginning. SIze mil. brass like this, and you should have good hunting ammunition set up just right for your rifle.
Thanks. I guess the options are:
1. 7.62x51 surplus ammo
2. USGI bolt
3. reloading, making cases fit the chamber, less 0.010" room for expansion
re: chrome plating
Do you chrome plate just the lugs? If you plate the whole bolt, all other dimensions will change. That could asking for more problems than it is worth.
The thing about reloading is the web will be stretched .020 after the first firing. Even with a minimal stretch with good resizing methods, how many times do you think its good for after that? Its a matter of how much you want out of it with the work and money you need to put into it VS ammo by the crate.
