I have a Colt compact that I have about 20K rnds through. I have tried many different spring combos and the ISMI FLAT wound spring is unbelievable! I figured this might be just the ticket for my MKV 38 super, given the short action length of these mini-guns they are hard on springs. After talking to ISMI I ordered 2 springs and proceeded to measure/cut/try. The spring works GREAT after trimming about 3/8 of an inch. You can still use all Detonics factory parts and it seems to lessen felt recoil a bit.
It's a good product, try it!