I was wondering if I could mount ar-15 traditional A2 style front iron sight to my Ruger SR 556. It's a gas piston rifle so I won't be using the gas block that is also the iron sights. Does anyone know if there are the A2 style front iron sight without the gas tube slot I want the front iron sight without the gas block. Another concern is I don't have the government profile barrel like the USGI m4 carbine have it has a heavy barrel, is the heavy barrel in the SR 556 the same diameter as the government profile barrel is. I was thinking if I can't mount the standard iron sight to my gun that I would have to settle on a detachable fixed front sight like a Daniel defense or something like that.