FWIW, if the concern is recoil, Ruger's new 9mm carbine has a lot less perceived recoil than the old Ruger one. I'm not start enough to understand, much less explain the physics, but it has a two piece bolt that somehow results in less perceived recoil than a fixed one piece bolt like the old one. Those two are the only PCC's I have, so I dunno how they compare to other ones.
As mentioned upthread, CMMG's 'radial delayed blowback' is another twist that's supposed to reduce perceived recoil as well.
Fwiw the CMMG radial blowback system eats ejector springs and I don't think it's been permanently resolved. Short 9mm brass hits the barrel extension on the way out unlike long rifle brass and the ejector system doesn't really like it.
I really like my SIG MPX 9mm SBR but unfortunately it has been the opposite of "cheap" - it runs great but $$ and tempts me to add more $. Only think worse is Sporting Clays OU or PRS rifle/scope.
Wish I would have posted this question sooner myself. I learned the hard way. I had picked up a PSA pistol w/ Glock lower awhile back. Finally got around to ordering a barrel, ALG rail, 3 lug mount, and adapter for my Octane. I could put up with the blowback, but the bolt slap / noise was not comfortable on the ears. Good thing is I made my money back on the pistol, and swapped out the Magpul grip to an A2. The Sig is truly a soft shooter since it is gas operated, but I kind of soured on the idea for now. But I would vote for the Sig MPX.
Taking a break from social media.
I have a bunch of these — HK, Dakota Arms, custom blowback AR9s, two MPXs and formerly a pair of JP blow backs.
There are great for shooting steel, and competing in PCC, but my experience based on mine and watching many more in USPSA, is that, as a whole, they break parts (MPX and AR9s) at a rate that would never be tolerated with a 5.56 AR, frequently have reliability issues due to being dirty (MPX) or with magazines (Glock mag AR9’s), and in semi-auto generally are not suitable for hard use, in a non-gaming/training scenario. The possible exception would be the MP5 pattern guns, but even those have peculiarities.
Likes pretty much everything in every caliber.
My "cheap" PSA AR9 16 inch blowback and the SIG MPX SBR (3x price of AR9)
GJM, how much of the reliability issues are the modifications to the 9mm "carbines" plus gamer ammo to win at USPSA? Seems to be a cottage industry to build/modify 9mm "carbines" to gain advantage at the sport. Saw the same things with pistols and eventually "racing improved the breed".
Every MPX I have owned, or had friends use, has eventually stopped working, due to parts breakage or a gummed up gas system. As you know, the barrel has to be removed to clean the MPX gas system.
Both my JP blowback carbines broke — one a trigger and the other the firing pin. Firing pins and triggers seem to be a constant wear item on the blowbacks.
Likes pretty much everything in every caliber.