I installed a Micro-click on my K-31. The rear one was easy, but the front one needed some filing. They're designed that way on purpose, so that you can get a tight fit. Get thee a sight base file at Brownells if you don't already have one. I filed it down for about 10 minutes and then pounded it in with a punch. It doesn't look pretty (the base of the sight insert is beaten up a bit), probably because it was my first one and I should've filed it down a bit more (but not too much). Note that I'm not exactly a candidate for Gunsmith of the Year - I'm a chairbound lawyer/CPA type. Believe me, if I could do it, so can anyone.
FYI, I put some RIG in underneath the front sight insert (prior to actually inserting it, of course) with a Q-tip. Then I put more RIG in all over the sight base, so the sucker will never rust. I intend to repeatedly hit the thing with more RIG far more often than it probably needs it, just because I despise rust (esp. on rifles with a history, even if they only cost $125).
Anyhow, it works just great. The factory sights suck (about the only thing on a K-31 that does), and the Mojos are a huge help. I didn't bring the hex wrench with me to the range, and didn't have much time anyway, but the group was pretty tight about 3 inches low of POA. I'll do better next time, because I won't be rushed, and because I've installed a smaller aperture in the rear sight (which allows for you to sight in on a smaller target much more easily and consistently).
Am I happy? Well, I just ordered the original Snap Sight for my new M39 (it doesn't have a MC, but one is being developed). The only difference is in how easy it is to change the elevation (big deal, I'll have to use the hex wrench instead of dialing it). If a repeat order isn't a sign of happiness, what is?
