S&W M&P M2.0 10mm (full size 15rd) to .40S&W 15rd magazine adapter

thingiverse

This shim allows you to use a S&W M&P .40S&W 15rd magazine in your S&W M&P M2.0 10mm handgun. I believe S&W currently makes the 10mm only in a full size frame (15 round with 4" or 4.6" barrel) while 40S&W version of the M&P comes in several sizes. The only magazines that I know will work are the 15 round mags from the full size M&P 40S&W. Smaller magazines for compact M&P versions will definitely not work. I would expect larger magazines to work but I don't have any to test with. I would hope I wouldn't actually need to say this but I will anyways, only .40S&W cartridges can be converted to use in a 10mm firearm like this. No other common cartridge can be converted (yes there are probably some other .40 caliber wild cat rounds that might work, but none are particularly common and I'm trusting if you know enough to know about those you know how bullets, barrel diameters, and chamber cuts match up). While it is possible to fire .40S&W out of the 10mm magazines that come with the gun I found that it created too many malfunctions because the feed lips of the 10mm magazine end much further from the breech face than a 40S&W magazine would. A 40S&W Magazine without the shim can lock in the 10mm frame but it is not properly located and I wouldn't want to try to use it like that. This shim pushes the .40S&W magazine to the front of the magwell locating it properly so the last round hold open works and rounds are positioned to feed correctly. This mod isn't perfect and does introduce a few excentricities: The shim is not locked in position so it can fall out when you drop a mag. I haven't had a problem with the shim falling out but I WOULD NOT use this for anywhere except training with cheaper 40S&W rounds at the range. 40S&W Mags will drop free for me when I push the mag release so long as the mag is empty and the follower is pushing against the hold open but may not drop freely if there are rounds still in the mag. Finally, if you drop a loose 40S&W round in the breach and close the action the ejector will not pick up the shorter 40S&W round, if you then load a magazine the next round will jam because the round in the chamber will not eject.