LRRPF52 Wrote:With that heavy of a barrel, and over 18" length, it makes sense to bed it. How did the extension slip into the upper? Was it loose, snug, tight? 30ft-lbs is on the light side for the Grendel. Try using anti-sieze on the threads, and set the tennon by backing off, then torquing repeatedly until you get to 60ft-lbs if you can.
The barrel was snug and I used anti-size grease on the thread. I tighten it up and loosened it few times as per instructions but I will do it again and try to get it closer to 60lb.
LRRPF52 Wrote:On the handguard, use an inch-lb torque driver to make sure the clamping force of the handguard is even, and not substantial for the MI SS Gen II. There has been some discussion lately about accuracy and clamp-style handguard mounting interfaces on the barrel nut.
Yes, Blue Loc-tite is one way of bedding it into the upper receiver tunnel. Since you have a clamp-on gas block, just use equal torque on the fasteners (inch pounds).
Do the same thing for the scope rings, setting them to equal torque specs. Wheeler recommends 15-20 inch pounds.
I didn't have a inch-lb torque driver, so I did it by hand, but I'll look into getting one.
LRRPF52 Wrote:If you're already well-versed in this, forgive my unsolicited remarks.
I always keep an open mind and appreciate when someone wants to help, especially when giving valuable advice - thank you! I've been shooting for years bolt rifles and I'm getting consistently 1/2" - 3/4" groups from my 22-250 and 308 rifles. I have a 556 Sig, but I'm not shooting it from the bench, so the advice on driving the AR will definitely help.