04-01-2014, 09:19 PM
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.
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.
Use a nice, solid rest, with rear bag. The AR15 requires some driving as opposed to free-recoiling like a bolt gun. Steady, firm pressure to the rear with the 3 remaining digits of your firing hand with straight pressure of the butt into your shoulder will help keep the gun tamed. If you're already well-versed in this, forgive my unsolicited remarks. If I really want to shoot groups and accuracy-test a rifle (something I have done professionally for a manufacturer day after day after day, from 0900-1700) I make sure I'm well hydrated, in a very calm mood, and I set up the position with the target in focus so that the natural point of aim of my entire bench position is directed through the center of the target.
Once I'm set up, ammo is on-hand, the gun is cradled or on bags/bipod, I get behind the gun and literally go to sleep on it, but thinking clearly in my mind what a good sight picture looks like. I then open my eyes, and settle the gun into the position by simulating recoil. Once I have a comfortable position that doesn't deviate from the NPOA, I begin my dry-fire drills until called shots are within maybe 1.5" of movement on a 100yd target, no more. I get my warm and fuzzy about the position, and then go live.
Once I do all this, I actually shoot fairly quickly, because there is no need to find the NPOA. It's already established, and the sooner I break the shot on consistent sight picture after sight picture, the better off I am.
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.
Use a nice, solid rest, with rear bag. The AR15 requires some driving as opposed to free-recoiling like a bolt gun. Steady, firm pressure to the rear with the 3 remaining digits of your firing hand with straight pressure of the butt into your shoulder will help keep the gun tamed. If you're already well-versed in this, forgive my unsolicited remarks. If I really want to shoot groups and accuracy-test a rifle (something I have done professionally for a manufacturer day after day after day, from 0900-1700) I make sure I'm well hydrated, in a very calm mood, and I set up the position with the target in focus so that the natural point of aim of my entire bench position is directed through the center of the target.
Once I'm set up, ammo is on-hand, the gun is cradled or on bags/bipod, I get behind the gun and literally go to sleep on it, but thinking clearly in my mind what a good sight picture looks like. I then open my eyes, and settle the gun into the position by simulating recoil. Once I have a comfortable position that doesn't deviate from the NPOA, I begin my dry-fire drills until called shots are within maybe 1.5" of movement on a 100yd target, no more. I get my warm and fuzzy about the position, and then go live.
Once I do all this, I actually shoot fairly quickly, because there is no need to find the NPOA. It's already established, and the sooner I break the shot on consistent sight picture after sight picture, the better off I am.