I have one on my .458 SOCOM. I love it. It locks up and down so it stays put where ever you put it. It uses standard A2 front sight posts. Combined with an ARMS #40A rear, I did not need a taller front sight post for the .458 SOCOM like you normally do with the #40 rear, or at least that is what they say on the Bushmaster sales sight. Back to the FA flip. This is exactly the same flip-up front sight that is sold by Bushmaster. Both FA and B's sights are made by [url=https://secure.valinet.com/~yankeeh/cgi-bin/web_store/web_store.cgi]Yankee Hill[/url] and is so marked on the front of the sight: YHM. If you buy it from Bushmaster is is slightly cheaper than buying it through Brownells, even with the dealer discount. Yankee Hill only sells this particular sight through certain outlets, as they will not sell it directly off their web site.