Just picked up the .052 FSP since I have a mid-length (Sabre with "F" marked FSB) and I noticed that the aperture is taller than the original A2 FSP by about 3 notches. Also, the notches are cut deeper than they are on the original so the retainer pin doesn't sit in the notch. It still keeps it from working itself out, but just barely and the site can cant either way by about 45 degrees. I added a small drop of blue loc-tite to the threads to help keep it from moving along with the spring tension, but is this acceptable, do I need to replace the retainer pin, or scrap the KNS altogether? Thanks!!!

Nobody tried these yet?

Alright, so are the A2 site posts plenty adequate for mid-lengths and carbines? Should I just pop the original back in and spend more time focusing on my shooting? The reason I changed it to the next smallest size was because I feel like the original A2 site post is just a fat bar that potentially gets in the way of things down-range. Am I wrong? Maybe if I had a 20 or 24" barrel, but up this close it seems like too much.

If the A2 sight is to fat, try an A1 post (worked for my wifes build). Or try one of the 1,000's target sights. Go to the Industry forum links and see what the dealers have. Good luck!
All the besthe                                                       B) FSB out of spec
Did the A2 sight fit? Try some other post, if they fit the KNS is f'd up. Send it back or sell it. Just my two centsATB

THe KNS post doesn't cant...it fits alright, but the notches are too deep for the retainer pin to engage and it's a little taller than the A2. I'd like to figure this out before trying to re-zero again.