This post is for about 7 people in the US as dumb as me to want to SBR a P250 module to shoot 22lr in a B&T USW-320 frame and then realize like $1200 into it that the mags only come in a compact and don't fit.

Two solutions:


Plan A) Get the Dremel and go HAM on the $350 grip module


or


Plan B) Make a 3D printed magazine extension and a jig for drilling a retention hole. The existing baseplate snaps on to a small protrusion and fits tightly. You'll need to source a 1/8th in pin (nail, roll pin, whatever, cut to fit), and drill each mag using the jig. A little filing maybe depending on your print settings, and the pin hole is undersized so you can get a nice tight fit on the mag.


I figure I put enough time into making this work that someone else in this spot might benefit, so here is the final product free for printing. And likely someone will post a "Some guy makes those on ebay" but anyway I had a good time making it. As a plus, it increases the capacity to 12.




Couple of different places to download a copy of the STL files to roll your own if you need it, I hope they are shared correctly:

https://thangs.com/Jt526/P250-magazine-Extension-34591

https://www.thingiverse.com/thing:5089939


The reason of all this with an extended mag in: