Medical limitations that developed the last couple of years have put major caliber rifles and shotguns out of my path for good. I have to limit long guns to things like .22LR, .22WMR and the 5.7 so I dove into the PS90 a while back just to have some long gun with at least pistol caliber terminal ballistics. I have not done the SBR but it is not as simple as rebarreling an AR, certainly people have done it on their own. CMMG is the barrel source.
It is just a barrel swap to get to SBR and I think the flush fit CMMG's take you from 16 down to 10.5 when installed. With the 16" in place it is barely a snitch over the 26" limit.
With the advent of Palmetto's AAC line the ammo has become much more affordable than even pre-pandemic times. Fiocchi who was loading for FN has established their own branded line. The American Eagle FMJ that Fiocchi is loading for Federal in their MO plant is crap for the PS90, I have had many instances of serious bullet setback, it was probably intended for pistols with a straight feed only. PSA's ammo is very accurate and about 50-100 fps hotter than the equivalent Vmax bullets loaded for the FN or Fiocchi branded ammo. It is possible to reload the cases once or twice, but I am not up for that just yet. There is a coating on the cases that will wear off quickly and then you get stuck cases or balky extraction when it is gone. This is a straight blowback action.
There are some ergo challenges for me with the PS90, but with
some aftermarket parts they have all been solved. Getting one of the aftermarket
low mount bases is mandatory unless you want to deal with a horrible level of offset and holdovers. There is a
fix for the trigger that helps but it is still a bullpup, you are not going to get to match level triggers in these.
Other than the problems with American Eagle ammo, mine has been perfectly reliable, and with good ammo it is a 1.5 moa rifle out to 100 yards or so. Lots of fun and everybody at the range wants to give it a try. Recoil is .22WMR level.
If mine were a pure range toy I would SBR it, but I figure that this weak cartridge needs all the barrel it can get for my purposes. I am getting 2450-2500 fps with the SS198LF ammo out of the thing. I think the local coyotes should still consider me a threat.