Can you use other brand rails on SR15s? I wasn’t sure if they had a proprietary barrel nut or anything like that. I know you need a special tool to install\remove the KAC rails but I’m thinking about putting a different rail (Troy or VTAC) and wanted to know if I’d have fitment issues after the KAC one was removed?
Considering that the gas block is hydraulically pressed on their not meant to really come apart for anything besides factory service.
So while there’s nothing to say you couldn’t put another rail on, the question of WHY is worth asking.
Well that’s not good… the reason was nothing fancy, I just want to be able to brace the rail against barricades when shooting but the standard rail leaves a lot of exposed barrel and limits where\how you can grab or brace it. I’ll have to figure something out because I really would rather something longer.
One option would be to send it out (e.g., Gun Gallery) and have the gas block shaved a bit (on the sides) and have a rifle-length URX II (or even URX III) installed. That should give you a little more room. You could probably sell your URX II mid-length for a decent amount to pay for the “upgrade.”
Give Neil a call at Gun Gallery in Jacksonville and ask him about it.
You can remove the block – it just takes some ‘encouragement’
A heatgun can help too sometimes.
I hope this isnt blasphemy in this forum 
but I had a Trox TRX put in place of the URX as you describe.