The springs are available now, the part number is 27749 and is the same for all the M&Ps, full size or compact. I did the same thing and modified a Glock spring that works. But only used this setup to check the new sights I put on. I will not carry the gun until I get the factotry springs. I ordered a few because eventaully I will be changing all the sights on my M&Ps. Anyway, call Smith and order a few. They are less than 2 dollars and it's probably a good spare part to have on hand.