I have a 16 lb 1911 spring in mine, a little more spring than came with it. It's preloaded, but really softens the blow and functions right down to soft ball stuff. I never shoot anything really light in it, though.
Yeah, my mag catch spring, a little flat spring, broke, too, couple years ago. A call to Ruger and there was one in the mail box 3 days later free of charge. That little spring is the only under-designed part in the gun and if it'd failed in a gun fight, I could have kept the thing going with pressure from the bottom, but it'd have cost me time to figure it out, not real pleasant to think about. I always carry back up, though.
I tried the 16lb Extra Power aftermarket P90 recoil spring for a while. I started getting some occasional erratic ejection patterns using standard pressure ball loads with the 16lb spring, although it handled a number of +P loads with aplomb. I discussed this with the tech at Ruger.
He suggested the heavy 16lb recoil spring might be a little too heavy for anything but the hottest loads, and might make the gun a bit more susceptible to grip influence issues. He sent me the newest recoil spring and explained that the use of +P loads was one of the reasons they finally went from using the same spring in the P90 as they did in the P89, to a slightly heavier one (going about a pound heavier, if I recall correctly). I tried a couple of other heavier "intermediate" aftermarket springs from time to time, and even the factory P91 spring (which was REALLY heavy, and something I decided wasn't suitable for me and the loads I used).
I pretty much decided to remain with either the "new" stock (heavier) spring, or one just a pound heavier for most of my purposes. Both did well with a variety of loads for me and made the gun seem to run better in my hands.
It wasn't the mag catch spring that broke in my gun, BTW, but was the actual mag catch itself. Snapped apart one day. Weird, but weirder things have happened.
Acceptable? I guess 1.5" 25 yard benched groups is acceptable. The first shot usually shoots a little low and opens it up from one ragged hole, not uncommon in autos.
Yep, the P90 does seem to exhibit acceptable inherent and practical accuracy for a service pistol. I suspect that with my aging eyes (and what my doctor calls a
soft 20/20
) I might wring a little more practical accuracy out of my P90 if I were to replace the original small profile/small dot sights with something a little more easily acquired. Maybe. Dunno. I've just been too lazy to bother, what with the gun already being reasonably accurate enough.
Mine doesn't put first shot being low, though, in either DA or SA mode. POA/POI remains the same for all of the ammo load. Just lucky, I guess.
I've also been shifting a lot of focus back over to revolvers in recent years, but that's largely due to my having been collecting and carrying a growing number of J-frames as off-duty, and now retirement, weapons. I actually started on SA revolvers & pistols, coming to DA revolvers somewhat later, followed by a reluctant adoption of traditional double action pistols (I had to start carrying an issued one back about '90).
I originally got the P90 because I'd long been a Ruger owner and was curious to see what they'd managed to do in the way of a .45 semiauto. The grip angle is good and the girth is just on the outside edge of what's good for my hands. Trigger is a bit more than fair for the breed.
Stages. Yep.
As much trigger time as I've invested over the years in TDA pistols and the ever-increasing variety of striker-fired DAO-whatever pistol designs (for work and as an instructor), I still find myself falling back on revolvers and 1911's when I'm shooting for sheer enjoyment and to push myself regarding my skillset.
