Fooled around some with a 1 in 9" .223. The 77 TMK was around MOA or so. The Berger 77 OTM did much better, and is a bit shorter bullet. I'm going to try it in a 1 in 7" Mk12
I bought three of the ASC mags, which allow an OAL up to about 2.31". Will try some 75gr Amax and other bullets, to see how they shoot.
I checked out the ASC site and saw that they make OEM mags for several manufacturers. Got me thinking...I have several different brand mags, plastic, steel and aluminum.
Got out the calipers and did some checking on the OAL possible with each.
Pmag plastic - 2.266"
Wilson Thermold plastic - 2.274"
Bushmaster Stainless - 2.313"
AR Stoner Stainless - 2.310"
Colt Aluminum - 2.264"
So, I think I will load up some 2.3" OAL loads and give em a try.
Always thought I was limited to 2.26"