I will say this.... buy aics mags not alpha. I just built a savage 6.5 creedmoor with cdi bottom metal. rifile will not feed last round in alpha mag correctly but feeds last round in aics mag and accurate mags just fine.
I use an Alpha Type 2 for my 260 (bottom rifle) and it also will not pick up the last round from the magazine unless I give the bottom of the magazine a slight push up. For me it is little more than an aggravation, but would be a major issue in competitions or true tactical work.