I'm having a tough time getting the barrel nut torqued properly. I have the right tools but the barrel nut adapter is being problematic...



If I use the alignment pin and leave it in there while torquing the barrel nut to spec, the pin is stuck with incredible force in the upper and will not come out with pliers or other means.



If I don't use the alignment pin to hold the adapter in place while I torque, I cannot get the adapter hole aligned with the gas tube hole in the upper.



Is there some other way you guys know of to hold the adapter in place?



If you aren't sure what I'm talking about, here's a video showing the basics of the install process: https://www.youtube.com/watch?v=c6EPT3sDyQQ

Does the 308 use the same rail adapter as the AR15 K-Mod? If so, I aligned the rail adapter where when I slid the rail over the adapter it was centered with the upper. Then, I marked the upper around the rail adapter as a visual reference while torquing the barrel nut. I then used a soft jawed pair of pliers to hold the rail adapter in place while I torqued the barrel nut to 35 lbs ft. (in your case 5 lbs ft more than the minimum torque setting for the 308 if its different than the AR15). I ended up using a pin punch inserted from inside the upper and through the rail adapter (but not out of the rail adapter) as well.

When torquing (with upper receiver threads greased, barrel nut threads greased, rail adapter threads greased, and outside of barrel extension greased), I torqued to 35 lbs ft., loosened, torqued to 35 lbs ft., loosened, and torqued one final time to 35 lbs ft.

It's very similar looking, yes.



Marking it may help. You used a punch from inside the upper huh? That's an interesting idea, although I'm not sure I'd be able to get that out afterwards either....

This is why I used a pair of soft jaw pliers. As I torqued the barrel nut (torque wrench pulling towards ground), I held the rail adapter from moving by pushing the soft jawed pliers in the opposite direction of the torque wrench. It did not take much force with the soft jawed pliers to keep it from moving. When I got my K-Mod about 2 years ago (from an online vendor), there were no instructions with the K-Mod; so it took several attempts installing it before I figured to use the pin punch and soft jawed pliers. I don't remember the exact size punch, but it was the largest pin punch that fit the rail adapter. After torqing (using soft jawed pliers in the process), the punch fell out on its own (had zero resistance since I was able to keep the rail adapter from moving).

When you get past this, when installing the rail; use a bubble level when tightening the rail in place. Place it across the top of the upper and rail to check the rail is perfectly aligned with the upper, and also the side of the picatinny rail (where K-Mod is laser etched into the side of the rail near the upper (both sides) to make sure it's also aligned in this plane.

Well, I changed out from the Geissele reaction rod to the more traditional barrel vise blocks and that seemed to help. I guess having the torque being resisted by the muzzle end (away from the part I don't want to move) instead of the barrel extension end made it a lot easier. It is now installed.



Thanks for the help.

had the same problem with my 556 model, but i used a pair pliers to get out the rod, still slightly of centered but i just deal with it for now, going to swap it out i think not sure yet i really like the BCM Keymod rail