Proof AI prefit on “old” rifles without QuickLoc

[samb300]

Not sure if I’ll get more hits in the bolt action or gunsmithing forum, but here goes.

What is the recommended method to properly torque a Proof (or Bartlein, etc) carbon fiber barrel onto a legacy AI that doesn’t have the QuickLoc quick change barrel feature. Meaning the AW and AWM series where the chassis is bonded to the action and without a custom fixture, you can’t get a vise onto the tenon shank.

The Proof drawing shows a flat machined at the muzzle, and it is marked “65 ft-lb Max”. Is that sufficient to keep a 338 Lapua barrel torqued on an AWM?

I’m assuming clamping the carbon fiber in the middle of the barrel is a no-no...

Let me know if anyone has figured out what the best method is here. Thanks!

Sam

 

[samb300]

What cartridge is your barrel chambered for? A grown man will be able to torque 45 to 50 ftlbs with a wrench on the flats.

338 Lapua.

Not asking if it ‘can’ be done, wondering if that 65 ft-lb at the muzzle is sufficient, when torque is typically 100 ft-lb at the tenon.

 

[NoLegs24]

Yeah, just went through this issue with proof carbon. I decided not to go with one of my barrels to put in an AWM. Just because I did not want to debond the action/ chassis.

And talking to Adam at Mile High, you have to torque that barrel 100ft lbs...

 

[samb300]

It would be interesting to know at what point you're stretching threads. I've heard 65 from a pretty reputable smith. But I imagine that also depends on the thread pitch too

I also don’t think 65 ft-lb at the muzzle, 26” away, with the torsion and deflection of the carbon barrel, is equal to 65 ft-lb at the tenon.

 

[samb300]

Yeah, just went through this issue with proof carbon. I decided not to go with one of my barrels to put in an AWM. Just because I did not want to debond the action/ chassis.

And talking to Adam at Mile High, you have to torque that barrel 100ft lbs...

Thanks. I think a short action caliber is probably ok, but on a 338 I agree that 100 ft-lb is ideal.

I wonder if a custom vise could be designed to work with the clearance afforded by the AW chassis.

 

[m1match]

A buddy is about to install a carbon fiber Proof in an AW and just torque to 65 ft-lbs so we'll see how it shoots. I've talked to a friend who builds rifles and his opinion was that it should be just fine at that torque.

 

[Supersubes]

I don’t think 65ft/lbs is an issue at all. Torquing it from the muzzle and twisting the carbon portion gives me the creeps though.

 

[Mute]

I don’t think 65ft/lbs is an issue at all. Torquing it from the muzzle and twisting the carbon portion gives me the creeps though.

There shouldn't be much pressure applied between the carbon fiber and the rest of the barrel.