Shim a Rem barrel ?

[Bruce W]

I have an xp 100 action that had the recoil lug and action face trued. I have a Rem take off barrel that I would like to use on this action. When I hand tighten the action to the barrel the bolt will not close. If I loosen the barrel less than 1/8 turn I can now close the bolt. The recoil lug is .182 instead of .187 (factory).
The tenon length on this barrel is .875 as my other barrels are .860 and .855.
I realize that by adding a shim to the barrel I would be extending the length of the case and therfore headspace issue

The caliber is 221 FB . I make my cases from 222 norma brass and I can control the shoulder location in the forming operation and can fit the case to the chamber.
OPTIONS
1. Best way ,take it to a gunsmith and have it corrected
2. Get another recoil lug
3. Add a shim to the barrel, I know this is not the correct procedure

But would the shim work. I Would use a stainless steel precision shim a hardened variety .

YOUR THOUGHTS PLEASE, Be gentle with me

 

[Preacher]

2 choices here, one is to use a shim knowing it's not exactly the correct way, or grinding a recoil lug to the diameter you need..

 

[boltfluter]

+1 on the correct recoil lug. Should work fine IMHO.

Regards, Paul

www.boltfluting.com

 

[Bruce W]

Yes, actually I would like to get a thicker recoil lug. Possibly oversized and surface ground to index the barrel correctly . Then fit my cases to the chamber. However the current lug is an xp 100 type that is pinned . So , no one makes replacement lugs for xp 100's that i know of. Lug would need a cut out for the trigger linkage and surface ground. The cost of this would probably equal a gunsmith barrel fitting. Plus the wait time. I believe a precision shim that will not mushroom on barrel tightening would work. Just my thoughts. Thanks, Bruce

 

[Bruce W]

Maybe if the shim could be sandwiched between the action face and the lug it may be a better option. You would have a straight force against the shim on tightening the barrel therefore no friction against the shim . This should lessen the effect of distotion on the shim. I have located a factory lug and will try that when I get it. It should be enough to allow the bolt to close. However the the barrel being fluted will not index correctly to the action. This is probably a cosmetic issue only. Bruce

 

[Preacher]

I would have no problem using a shim if it came to that, and really see no big problem doing it, other than it may not be politically correct to do so 'O)

 

[Dusty Stevens]

Put it in front of the lug. Dont mess up the geometry of the trigger mech

 

[STS]

The lug you have now measures .005 less than a untouched lug and your bolt won't close. If you get a .187 factory lug you know that at the very most you will have .005 end clearance on the bolt nose, maybe less. .005 clearance is acceptable in a clean environment rifle, but a field rifle probably should be on the order of .010. Do you have a depth micrometer to check some measurements on the action? If so, we can do the math to check clearances from the bolt nose to the barrel tenon. I would avoid the shim scenario if at all possible.

 

[carlsbad]

1/8 turn is about .0075" which is consistent with the difference in lug thickness.

I wouldn't worry about the shim not staying flat. Between 2 flat surfaces like that it will be fine. It is not thick enough to significantly affect the stiffness of the joint laterally (mass of barrel moment). Lubricate it well. I like to used nickel anti seize in this joint.

Where do you think you'll get the shim?

--Jerry

 

[Bruce W]

Most sources for shims offer 1.000 I'd or 1.125id. Still searching for 1.062id . Had a feller on this site contact me that has a bunch of lugs. He's going to look for a fat one for me. I'm going to wait for factory lug and see what happens. Kiff has thicker lugs but to surface grind .020 would be stupid also. I do have a depth mic recess in tenon .150 tenon length is .875. I' m at work so measuring to the bolt face will have to wait til tomorrow. Thanks for your input. Bruce

 

[Bruce W]

Measured action : with 473 bolt Recoil lug to locking lug .880 Measured with bolt cocked and recoil
Recoil lug to bolt nose .723 lug included
Measured action with .378 bolt Recoil lug to locking lug .877
Recoil lug to bolt nose .726

Original 35 rem barrel tenon .867
recess .148
PPC barrel fitted after action was trued tenon .858
recess .156
221 lvsf barrel I want to use tenon .875
recess .150
Now to compound the problem further ,I have a PTG bolt coming to use on this project.
I am wondering if the 221 barrel may have been unwittingly machined at the shoulder or an oversized lug was previously used. A previously fired case that was sized for an xp 100 fits the chamber with about .002 protruding from the end. So if i make a shim or recoil lug I will have case that is about .015 longer in the case body. Now when i full length size I will possibly not be sizing enough at the bottom of the case with out pushing the shoulder back.Maybe a P Bike ring die to take care of the sizing at the web area of the case. Common sense would say reduce the tenon length and have the chamber lengthened accordingly.That way it would be usable if I wanted to pass it on( Make it right so to speak) So much for the idea of buying a barrel and hope it fits. Yeah, I knew I was risking this when the barrel was purchased. Just sayin. Bruce

 

[Roeder]

Very likely that with your new PTG bolt, the length from the back of the lugs to the front, bolt nose, and bolt face will be longer so either the bolt or all your barrels will need to be adjusted.

The dimensions of your last barrel, the .221FB sound closest to factory typical. My guess is that the other barrel tenons are slightly shorter to make up for the smaller dimension of the surface ground lug and any other truing that may have been done such as truing the front of the receiver, bolt face, etc.

 

[Bruce W]

. So your saying that the tenon length is normal at .875

 

[Roeder]

. So your saying that the tenon length is normal at .875

Yes. I measured a couple of take off barrels just to check my memory and they ran about .875 to .877. Even so, it is always best to measure your individual action and lug trued or not.

 

[Bruce W]

As it turns out even with the .187 lug i just received the bolt will not close when the barrel is tightened against the action. Ironicly when the barrel is tightened by hand the bolt closes. next step is to find someone to chamber and trim some clearance for 221. Or sell the barrel. Must be that few thou. to true the action. Bruce