Can you shim a barrel .01?

[joshb]

I’m wondering. I have a Bat SV and a Stiller in 6.5x47. The difference in the length of the brass shoulders between the 2 guns is exactly .01. The Bat barrel is the shorter and about 3 thousands longer then new when fired. My die just barely sets it back enough to get the 2 thousands “play” on my reloads. I got to the range this past weekend and grabbed the wrong box of ammo. The first cartridge in the gun, I went to close the bolt with “gusto” and it got jammed. It was rather difficult to get out. I’ve been thinking. It would be great if all my brass could work in both guns after sizing to one length.
Can I have a shim made to fit between the barrel and action or is .01 too much. Pardon my ignorance. I’m a wood guy. I have a big knowledge gap, here.

 

[Dusty Stevens]

Dont do that. Have your gunsmith run the reamer in to adjust the headspace

 

[JohnKielly]

Also, you don't know if they're dimensionally identical otherwise. It may be cheaper to get another shell holder & modify it to give the short chamber more bump. Admittedly that would necessitate you keeping on the ball about which cases you're sizing, so it's not the greatest solution.

Whatever you do, don't let any gun plumber pein the shoulder of the barrel to lock it up longer.

 

[joshb]

Thanks Dusty. I’m looking for why. I guess my real question is “ How much gap does a competent smith leave between the bolt and the barrel? 1 thousandth? 2 thou? .0005?
Thanks for any enlightenment. Bob Green does all my work. I just didn’t want to bend his ear with a dumb question. Josh

 

[boltfluter]

Josh,

Usually .005 - .010 clearance is normal.

Paul

 

[alinwa]

Thanks Dusty. I’m looking for why. I guess my real question is “ How much gap does a competent smith leave between the bolt and the barrel? 1 thousandth? 2 thou? .0005?
Thanks for any enlightenment. Bob Green does all my work. I just didn’t want to bend his ear with a dumb question. Josh

This though isn't relevant even though it may look like it is. That gap has nothing to do with headspace.

Some here will say this is crazy insane but...... another option is to have your gunsmith hand-ream a thou out of the short one. I have tooling to do this without even removing the barrel. I have slammed out 5 chambers, leaving them all a couple tho short and then tightening/timing etc and last step hand-reamed them all to absolute perfection.

It's actually brilliant.

Just like Kiff's uni-throating system is brilliant.

But there will still be plendy "gage guys" who think it's "inaccurate". These will be the same guys who "polish out their chambers to give them a nice crosshatch"

The same guys I FIRED, because they are physically unable to make two chambers the same.

 

[BoydAllen]

To the OP, did you mean .01 or .001? The former, ten thousandths, would be quite a lot of difference and guarantee that at least one of the chambers is out of spec.

 

[hoz53]

I’m wondering. I have a Bat SV and a Stiller in 6.5x47. The difference in the length of the brass shoulders between the 2 guns is exactly .01. The Bat barrel is the shorter and about 3 thousands longer then new when fired. My die just barely sets it back enough to get the 2 thousands “play” on my reloads. I got to the range this past weekend and grabbed the wrong box of ammo. The first cartridge in the gun, I went to close the bolt with “gusto” and it got jammed. It was rather difficult to get out. I’ve been thinking. It would be great if all my brass could work in both guns after sizing to one length.
Can I have a shim made to fit between the barrel and action or is .01 too much. Pardon my ignorance. I’m a wood guy. I have a big knowledge gap, here.

josh-the shim idea wont work. reaming both chambers with the same reamer to the same headspace to start with would be the way to go. have these two guns been chambered with the same reamer? if not other chamber dimensions may be different also. i would keep the loads seperated for individual guns.

 

[butchlambert]

Thanks Dusty. I’m looking for why. I guess my real question is “ How much gap does a competent smith leave between the bolt and the barrel? 1 thousandth? 2 thou? .0005?
Thanks for any enlightenment. Bob Green does all my work. I just didn’t want to bend his ear with a dumb question. Josh

Bob is a great guy.

 

[alinwa]

To the OP, did you mean .01 or .001? The former, ten thousandths, would be quite a lot of difference and guarantee that at least one of the chambers is out of spec.

Not the way I see it........

the gage guys generally strive to "just drop on the go gage" but are allowed a couple thou over and still be "in spec"

And new brass is often .002 to .004 under the go, for a real-world variation of .005-.006 easily spec'd "acceptable."

 

[243winxb]

“ How much gap does a competent smith leave between the bolt and the barrel? 1

And the real question was......

 

[gunsandgunsmithing]

To the OP, did you mean .01 or .001? The former, ten thousandths, would be quite a lot of difference and guarantee that at least one of the chambers is out of spec.

I agree Boyd. The paramount issue, assuming shimming corrects the headspace is that shimming also affects how much unsupported case there is. I'm not a fan, but then I get bashed on here for saying that using a thicker recoil lug on a Remington is a bad idea, for the same reason and because it creates the same problem. Same, same..but different level of acceptance, apparently.
Ultimately, it depends on how much unsupported case it creates but also, the amount of clearance, particularly on a Remington, is a safety feature incorporated into their 3 rings of steel design...A very good system that becomes compromised by excessive clearance between the bolt and barrel. I prefer .003-.005" clearance here.

 

[luckyshot52]

As one person points out one of the chambers is cut out of spec. A gunsmith needs to check them to see which. Then using the same reamer they could be matched. If it is the long one it could eventually start having case head seperation.

 

[Ggmac]

.003-.005 also . Bolt nose to barrel . I want the least amount of cartridge exposed . I was brought up on old 6 PPC brass that was super critical to have min case head protrusion .

 

[alinwa]

C'mon.... cone VS Rem700 VS flat-faced barrels and bolt noses from pre-64Win to BAT. Extractors from Sako to 700 to Mauser to M16 style......"unsupported case" gets a lot of play but I've seen them from touching to ten thou off..... I've seen gaps you could throw a cat through on conversions and plain old screwups. I've seen cutouts for extraction that actually-factually distorted caseheads.... but none that ever "blew out"... there are setups that as designed show less support than leaving a 15thou gapspace on a custom. (puh-LEEZE haters, keep it on the inside....I'm not advocating 15 thou clearance )


And I've seen several thou variation in web support in same brand cases and 40 thousandths difference from brand to brand. Real life ain't NOBODY blowin' holes out the sides of the webs on today's setups....


IMO


al

 

[BoydAllen]

As long as they don't forget that having correct headspace is not the same thing as having the correct "gapspace"....IMO with all of the fellows who have bought lathes to do their own work, I do not think that some discussion is a bad idea.

 

[Dusty Stevens]

Everybody needs some plastigage

 

[alinwa]

As long as they don't forget that having correct headspace is not the same thing as having the correct "gapspace"....IMO with all of the fellows who have bought lathes to do their own work, I do not think that some discussion is a bad idea.

Boyd I couldn't agree more re the discussion!

After all, isn't discussion the sole raison de'etre' FOR a forum?

Doesn't "forum" the word itself MEAN discussion?

It's just that "discussion" means people disagree..... "discussion" BY FIAT means DIFFERENT points of view are aired......the fact that you have to say the words

...... I do not think that some discussion is a bad idea.......

Shows where we are.... There's a PROBLEM in River City!

When people are reluctant to DISCUSS on a forum, there's a problem.

When worldviews don't CHANGE because of this discussion, there's a problem.

You're a teacher fer cryin' the blues, you know more than any of us where conformity leads!

And yet... AND YET.....there's a lot of folks here who just get their wee hienies all up in a snit when their worldview is threatened.

 

[Boyd L.]

Everybody needs some plastigage

My first and only use of plastigage was for selecting appropriate shim thicknesses for the rod and main bearings on a Model C Allis-Chalmers tractor. Purred like a milk fed kitten.

 

[hoz53]

I’m wondering. I have a Bat SV and a Stiller in 6.5x47. The difference in the length of the brass shoulders between the 2 guns is exactly .01. The Bat barrel is the shorter and about 3 thousands longer then new when fired. My die just barely sets it back enough to get the 2 thousands “play” on my reloads. I got to the range this past weekend and grabbed the wrong box of ammo. The first cartridge in the gun, I went to close the bolt with “gusto” and it got jammed. It was rather difficult to get out. I’ve been thinking. It would be great if all my brass could work in both guns after sizing to one length.
Can I have a shim made to fit between the barrel and action or is .01 too much. Pardon my ignorance. I’m a wood guy. I have a big knowledge gap, here.

I did think there was a typo and you meant .001. I see that’s not the case. Still i will stand by my first post.