Gunsmithing Barrel nut torque - what's "safe"?

BasraBoy

Gunny Sergeant
Full Member
Minuteman
Mar 29, 2008
2,355
3
60
Dark Side of the Moon
I'm installing a VIS monolithic upper on a rifle.

In the "instructions" sheet that comes in the box it mentions torque to "no more than 40 ft lb" but gives no max/min torque range.

The most I can seem to get it torqued to is around 25-27 ft lb (the barrel is a Sabre Defence 16"). If I try to go higher there is no movement on the nut but the upper starts to twist on the vise block.

The vise itself is as tight as I can get it (so that is leaving jaw marks in the block!)

Headspace is fine but, before test firing the rifle I wanted to check if this is torqued within safe limits in the collective experience.

Thanks in advance for your help.
 

bowslngr

Sergeant
Full Member
Minuteman
Dec 29, 2009
311
1
55
North Carolina
Re: Barrel nut torque - what's "safe"?

I have no experience with monlithic uppers, but my experience tells me that 30 ft-lbs is the min that you can get away with for standard barrel nuts.
 

BasraBoy

Gunny Sergeant
Full Member
Minuteman
Mar 29, 2008
2,355
3
60
Dark Side of the Moon
Re: Barrel nut torque - what's "safe"?

Thx - maybe I'm just being cautious but when the upper starts to look like it is twisting in the block I get nervous about damaging it.....