I know i've had at least 3 of the BK's, probably more, but i can recall them on a Colt Cobra which got fired with +P's (and yes Colt did rate their aluminum frame guns for +P), 2.5" 19's and 66's, and a 29. My hands aren't all that big and i actually prefer magna's and an adapter over the factory targets. Pretty sure i also used one on a 27.

Roger