This should have been standard on sig 556 - Samson SIG 556 Rails - STAR-556 - Short Pistol

Easy to install. Great look. I like that it used the bayonet lug for mounting. gives additional strength. The new rali extended further back than the original and touched the portion of the lower just in front of the butt stock folder. May not be a problem, but I noted that this made the rear receiver pin hard to insert. You could also see a gap between the upper and lower receiver. This binding bothers me so I will file off a very thin amount of the lower receiver where the rail extended. The bare metal will be hidden when the upper is pinned in place. I suspect that if I do not file the material it will eventually wear the surface finish off anyway. Samson could remedy this by cupping the underside of the rail where it extends over the lower portion of the receiver. Other than this one item The fit and finish is excellent. I like this design better that the Troy rails because you get to keep the existing front sight or replace with a folder. The Troy rail uses the SIG front dovetail to mount secure the rail. Therefore you cannot keep the original sight.
Pros: Looks great, Easy installation, Well Made
Cons: The read of the rail touches the lower and required a samll aount of filling for clearance

This review was written in the old system and had content requirements that are different than reviews written today.