Guys, I've been looking for a handguard for a 12.5" build I'm starting to pencil out (the idea is "GL/SSC upper with more modern furniture"), and as I build a spreadsheet and come up dry I thought I'd ask y'all, especially Stickman as a GL/SSC owner if he sees this, for suggestions.

Looking to the original GL/SSC for inspiration, the RIS II is "FUGGEDABOUTIT!," though supposedly some were built with Middy KAC URX II's over lo-pro CAR gas blocks. The URX *can* be had, but it's getting rare and expensive where I've seen it.

Things I'm looking for:
  • Hard 11.75-11.78" upper length limit to ensure theoretical suppressor capability just in case SHARE Act does make it through without having HPA stripped out.
  • FSP slot. I haven't found many with this, and most of what few there are are too long.
  • Would prefer seven sides of MLok or Keymod plus top-rail--the only FSP-slots I've found so far are quadrails.

I suppose I *could* just slap a rail-mount fixed sight on, but I'm partial to integral FSP's for CQB builds. The ideal would be an even longer, wrap-around-post version of Vltor's CASV-EL, but they're not even doing any more of the versions they DID make never mind a one-off custom. Or I could have a machine-shop cut an FSP slot into the top rail of a generic octagon free-float, if I can find one at the right length...

Anybody know of anything that fits, or am I better off to just suck it up, look for a free-float octagonal at the right length or a URX II and slap on a rail-mount BUIS? (Rail mount would have the advantage of longer sight radius, though...)

BTW, I found some more info on the GL/SSC: The Marines list the URG as part of the authorized equipment tables for Annual Rifle Training--I don't take this to mean "standard issue" but rather "if you've somehow laid hands on one you can use it to qual." NSN's are 1090-01-D12-0982 (listed in the last ART docs publicly released, which are 2016) for the lo-pro RIS II URG, though it's listed as "12.25" barrel", and somewhere along the way I found the RIS II FSP version of the URG listed as 1090-01-D12-0983. Those might be start points for tracking info down for somebody with inside connections, though none of the NSN search sites I've found come up with anything. They both have TAMCN code SFE09, which maybe some of our Marine members can help make sense of, though my gut guess would be something like "Special Forces Equipment, Fiscal '09."