Because everyone has a slightly different way of building the 9mm PCC, they can be finicky and incompatible. As a bullet hose, an overweight buffer and stiff spring should get you there though for normal operation. The more you do to flatten out recoil, the more... gamer-ish the gun will become. Mine shoots great on splits with little dot movement, but I'm shooting a tailored load. I have a short stroke kit with an oversized plug so my hardware reciprocates even less than normal, my LRBHO isn't even installed in the gun (nor is my bolt stop). If you're wanting to spray and have some range fun, a Ruger PCC and a couple of cheap ETS Glock-pattern mags will yield you a low-recoiling, low-effort gun that's fun to shoot, utilitarian, and will eat anything you feed it. It's not the fastest in the world, but it's durable, cheap, accurate, and a great truck gun with the takedown feature.