Gunsmithing bolt face play, how much is okay?

[pawprint2]

How much bolt face play is okay in your experience? For example: a 6.5x55 with a base diameter of .480, and a 30-06 base diameter of .471, rim thickness, .059 vs .049 respectively, good to go with same bolt face? How much variation is commonly acceptable in precision rifle builders terms? I realize you may want a different bolt face for a .223, if you were going to try to change calibers from a 308 to a 223, but what is the common wisdom on how much is too much, and how much variation is O-K?

 

[alfson]

I recently had my Savage 110 rebarreled from 30-06 to 6.5x55 with no change to bolt. It works fine so far. Shooting Prvi Partizan 139gr FMJ while waiting for Match ammo orders to arrive.

When I tried feeding the same cartridges through a 1903 Springfield the rim didn't want to slide up the bolt face. I don't know if the problem was with rim thickness or the rim diameter or both. Since none of my Springfields will need a new barrel anytime soon I won't be investigating any further.

 

[seanh]

Just get some go/no go gauges for what ever caliber you have.

 

[Stokes]

Bolt face concerns have more to do with extractors than just about anything else.

 

[seanh]

Good point. Depending on the rifle, one or the other, sometimes both can cause issues.


Based on your last question, you always go by standard industry specs...hence go/no go...some people use a piece of paper, tape on the back of the case.


What are you trying to accomplish?

 

[xs hedspace]

He's not talking about headspace, just the rim diameter difference. I wondered myself if a PPC rim cartridge would work in a Mauser bolt action, like extraction problems.

 

[glbreil]

There are a lot of benchrest shooters who shoot a PPC in a standard 308 bolt face action. The only issue is extraction. If the bolt will reliably pull the case it will be fine. Going the other direction it just needs enough clearance so that it does not bind when closing the bolt.

Thanks Gary

 

[alfson]

After spending some time talking to a gunsmith, the answer seems to be " it depends"

Is the gun push feed or controlled feed?
What kind of extractor do you have?
What kind of ejector do have?
How much are you willing to spend for me(the gunsmith) to make it work for you?

It appears that most standard Mauser size (.473 rim diameter) push feed bolt faces will work with Scandidnavian (Krag-Jorgensen or Carl Gustav ) .480 rim diameter cartridges. The controlled feed bolts may or may not depending on manufacturing tolerances, design dimension and type of ejector.

 

[MikeeBooshay]

There are a lot of benchrest shooters who shoot a PPC in a standard 308 bolt face action. The only issue is extraction. If the bolt will reliably pull the case it will be fine. Going the other direction it just needs enough clearance so that it does not bind when closing the bolt.

Thanks Gary

True, but not with stock Remington extractors.


Some of us also shoot a 308 face cartridge ( 30BR) in a 6PPC, but have to rebate the rim on the brass.

If the question from the OP is can I shoot the 556 from the 308, the answer is not very well you can't.

Making a 223 feed in a 308 action ain't easy either, even if you change the bolt.