Grendel II chamber

[NugginFutz]

Projectiles with more of a secant ogive can get mis-aligned in the bore if they jump too much at Grendel pressures in the AR15. That kind of jump equals bad accuracy, unless you load tangent ogive pills as far out as the magazine will allow, like the 130gr Sierra Game King, the 85gr Sierra HP, pills like that. Then some will say, "Just drive the projectile faster into the lands with more pressure."

I would have to agree with you there, LRRPF52. I found my BHW quite selective about what it liked. When working up the load it finally approved of, I discovered it had more dislikes than likes, with respect to the 123 Amax. I needed to really knuckle down and tune the load to find a node that was wider than .5 grains. Fortunately, I had shot an OCW with enough steps to spot it, and was able to go back and locate the sweet spot. Seating came next, which proved out that the tube liked them long. I believe that it would have been not nearly as tedious, had I been developing a load for a standard Grendel chamber. The data I collected while developing my load reminds me very much of the way a U-2 flies at operational ceiling. It's a 5 mph envelope, where flying any slower will cause a stall. Any faster and the wings go unstable. Not much room for error.