Careful what you use this on! - Leapers UTG Tactical Front Sight Assembly for Mossberg 12ga Shotgun and Variant

I already reviewed this once, since I have it on an H&R Pardner Pump with the match rear sigt on the pic rail. I wanted to put this on my Mossberg Shockwave and brace set up, for improved sighting. NO GO!! The sight will not open up enough to accomodate the thick walled barrel of the Shockwave. I imagine the heavy 590 barrels could be a problem too. It works fine on standard bbls, but the heavy duty ones can be a problem!!