Fixed: 18" Alexander Arms barrel: 2.5+ MOA

[c3k]

Piston set-up and an untorqued barrel from the extension are where you need to look before even worrying about accuracy.

Any time you're torquing on a muzzle device, the barrel needs to be isolated, not clamping force on the upper, which is a separate part.

I wouldn't have high expectations from an external op-rod gun in accuracy, unless the gas system was pinned and the barrel bedded really well.

Short story is that there are major issues with a lot of the components and assembly methods you used, before we can even talk about the barrel's accuracy potential.

Another thing with Grendel AR15s is that you have to shoot them differently than .223 ARs in most cases, since the projectile weight and recoil make the gun handle a bit differently as to positional shift.

Thanks for looking at my thread. I'm happy to hear of better assembly methods (but, I didn't really mention mine, did I?), and am a neophyte to the AR build world with only a dozen to 15 builds. Certainly nowhere near your level.

When I UNSCREWED the muzzle device, I used the upper block. Why? Well, I certainly did not expect it to spin the barrel off. I used my magpul bevblock when I tightened it on, back in the spring.

I've built and used 5.56 and .223 Wylde ARs with external op-rods. I certainly did not expect the poor accuracy from my first 6.5G that I saw.

When I get the barrel back or if Alexander Arms replaces it, I'll put it together again (using my assembly methods, as good or bad as they may be ), and report back with some range pix.

Without getting too expensive, which of my components would you change, and why?

Thanks,
Ken