I bought one 10 round mag from MDT but found out, after it arrived, that the plastic follower and the molded top restricted the O.A.L. to about 2.830. I get the best results when I seat my Hornady and Sierra Bullets out past that.
I ordered an all-metal 5-round AI mag from Brownell's that has about 2.895 available length for O.A.L. and that was what I used for the loads I shot ( 2.858, 2.845 and 2.835 wouldn't fit in the MDT magazine).
It feeds great and drops right out of the mag well when you press the release. The MDT mag doesn't do that.