I've never bought from SWFA, I thought I read where somebody had some issues w/ them? I recently ordered one from optics planet and it was about $75. They easy to deal w/ best I remember.
Back to the point, they do work! If you go the whole 9yds when setting up a new rifle ie breaking the barrel in, lapping the rings, replacing the trigger. The rifle I have one on is sub moa @ 100yd w/ Hornady ammo and probably the reason I'm posting is I put in on the bench at 300 yd on sat and was making some 1.5-1.75'' groups. Couldn't be more please.