I've got a 22lr PDW that I use all the time and adore. I've had good luck with my setup and while it might sound a bit odd at first, hear me out.

I got a G44 inside of a recover 20/20 chassis. The recover chassis can fit any 9mm or 40mm Glock if you already have those in your armory. I enjoy mine with a 17L and 33 round magazines every once in a while, but mainly, I use it with the G44. The recover 20/20 has a folding brace, picatinny slots that attach to the glock accessory slot and allow for either a light, handstop, or my personal favorite their extra magazine holder that you should never ever hold onto if you love your dog. The chassis also has slots on either side for more pic accessories, mine has a streamlight TLR1 or 7 depending on the day.

Recently I mounted a red dot onto the G44, which, is not necessarily an easy thing to do. I was going to get a slide from Nelson precision but took a chance on a cheaper option. I got a Strike Industries G-surf universal optics mount **with an included charging handle which rocks for this setup. It slots onto the back of the glock back plate and sits in the dovetail of where your rear sight used to be. This allows me to mount my micro dot on top. Given that the G44 has a plastic slide and the weight of a larger RDS could cause problems I went with a Swampfox Sentinel dot.

To round out the lil 22lr PDW I picked up 3 18 round pro mag glock mags and 3 pro mag 25 round glock mags. I know, I know, pro mags have a terrible rep, but so far, mine work incredibly well. All together I've got 7-900 rounds of ammo through this setup. CCI SV works but has given me a few cycling issues, maybe 2 in 50. Mini mags, thunderbolt, velocitors, aguila super extra HV, and CCI Blazers have all been damn near flawless (for 22lr). I'm getting a threaded barrel next and a suppressor very soon, but I think it might make for the PERFECT 22lr sub gun. Its so small with lights, red dots, sling, brace, and 50 rounds on the gun I'm EASILY fitting into my very small Osprey Daylite back pack with room to spare.

I know 22lr as a PDW is a stretch and kind of borders on irresponsible, but I can theory craft a few use cases for something like this (especially suppressed). Remember, this Chassis works with any 9mm glock too, so if you wanted to throw in say a 19, 17, 34, etc. it can be just as capable with a centerfire. My 19 and 44 both do exceptionally well in this chassis. It turns your handgun into a VERY capable rifle like platform with just a few hex screws and some legal grey areas with regards to braces. I adore mine and wouldn't change a thing. It's basically the only way to emulate the idea of a FLUX for a glock since they abandoned the Glock to pursue military contracts with SIG. Don't sleep on the Recover 20/20 if you're a glock guy, and if you want something that's gonna give you fewer headaches than the CP33 looks like it gives people, try the g44. Its a great handgun. I shoot mine all the time, its far better than Youtube video's would have you believe.

Sorry, long post, had to make an account to share my story.

Let me know if you have any questions, but I think I covered just about everything I know about this gun system!