Top Gun Had this in stock when Sig did not (and has not after being on backorder for a while)....Sig Rails are plastic but seems to be holding up good..Top Gun Online Service & Shipping was on point ...TG is just that..>>>>>"Top Gun"

I typed PLASTIC in caps on purpose because they dont hold up well. I mounted a rail style bi pod on the lower rail which worked fine for awhile. Was at the range the other day and the gun wanted to move around alot. I noticed the bipod was angled rearward. Looked and saw the bi pod had broken the ridges on the side of the rail. If they can't hold up to .22lr a .223 will tear them up. Looks like I'm going to have to graft an aluminum rail onto the bottom to fix the problem, or Sig could of just made them out of aluminum to start with.

Just mounted these rails on my Sig 522 and the only reason I didn't give the "excellent" rating was the bottom rail had to be slightly reemed to fit perfectly flush. I imagine 99% of people would have not cared about the very small variance as it did fit without having to reem. But for the anal retentives out there, you may have to do this for a perfectly flush fit.