Here are a few choices, I've tried most of them. The SpringCo w/white spring (not using presently, works but didn't like the secondary spring function when I had to "show clear" at the end of a course of fire). Various Glock recoil set ups captured and un captured. (min. 13# spring). If you decide on trying the Glock set up?, do the Glock recoil spring function test.... hold the Canik vertically in the air (unloaded), pull trigger, does it ALWAYS go FULLY back into battery when you reset the slide with normal pressure, manually or not???... If not, the recoil spring is not strong enough...I've had a few times (using a Glock 13# recoil spring that the slide would NOT fully return to battery, .....that was enough for me to guess in competition I might have a not have full slide lock up / or a out of battery situation). I decided to see what could be done with the "stock" Canik recoil spring/rod.... (This disassembly procedure is shown on UTube or the Canik forum) or look up my Canik posts here , detailed to do's.... (compress spring, hold with vice grips, gently heat nut , remove nut, cut spring coils, put spring back on rod, compress spring, w/vice grip, a dab of blue locktite on rod, remove vice grip.....Remember if you cut too many coils off you are SOL, go slow 3/4 coils seem to work well for me.........IF someone made a 14# recoil spring for the Glock/Canik????, I'd think that work work for us. 100%???.... Haven't found one yet...... Love those Acme 145/147 red bullets w/ either n320 or TG..... Kudos to MR. Bullet feeder, just put one on my 650, ingenious device,