I took some time today to field strip Manda's new gun and take some shots of the insides and some comparison shots with the "real steel" M&P9.
Obviously, the hole in the muzzle is smaller on the little one, and you can make out the barrel nut that holds the barrel assembly together. It is the same setup as the Walther P22, unsurprisingly, and P22 thread adapters work if you plan to use the M&P22 as a suppressor host.
The slide on the 22 seem to have slightly sharper corners than the 9, and the polymer is smoother, as well as the finish on the slide being somewhat different, more of a satin black than the 9mm's finish.
Externally, they're pretty much a match. Both have the hinged bottom half that acts as a trigger safety, and feel the same against your finger. Internally, there's a bit of difference in how they work, which I'll get to in a bit, however the end product is a better feeling trigger than what S&W is putting in the centerfires (primarily due to the striker system.) Take up and break are near the same as my M&P9 with Apex parts installed, although a little lighter; but where it really shines is the reset. It's audible, tactile, and about 3,879 times better than the centerfire's trigger.
The sights are similar, but obviously not identical. The 22 is cut similar to the 9mm's, however there is only a single white dot on the front sight blade, and the rear is adjustable for elevation, as well as the normal drift adjustment for windage. Elevation adjustment is a nice touch on a .22lr, given the inconsistencies common in different .22lr manufacturers.
The 22's thumb safeties are actually slightly further rearward than the centerfires, which causes MandaFern to have difficulty getting a good high thumbs forward grip, since it's just barely too much of a stretch to ride the safety for her. It's not a show stopper, and on the M&P9 and my 1911, her thumb instinctively goes where it belongs.
Another con (for me) is that it has a magazine disconnect "safety," and it doesn't seem to be as easy to defeat as the centerfire's is.
Takedown is a bit different on the two guns, the 22 requiring the slide to be fully forward, and the takedown lever needs to be pulled out about halfway from the frame, then takedown is consistent with most blowback pistols I'm familiar with (pull the slide to the rear, then up and forward off the barrel.)
Now we can start to see some of the internal differences between the S&W centerfire M&Ps and the Walther built .22lr version. Most notably, the barrel is fixed to the frame, held in place by the barrel nut pressing against a barrel shroud and tensioning it against the frame, identical with the barrel system on the Walther P22. The rimfire pistol also does not have a captured recoil spring, unlike the centerfire guns.
The barrel extension has a nice little ramp cut in to help with feeding-
and the magazine definitely shows the Walther rimfire heritage-
M&P22 on left, P22 on right.
What surprised me about the M&P22 however, is that it is not a striker fired gun like the centerfires, or a DA/SA like the Walther, but is actually a fully shrouded Single Action hammer fired system.
No wonder the trigger feels good!
Hopefully we'll have a chance to get out this weekend sometime and get some rounds downrange and see how it feels and shoots.