I'd love to see a picture of PRI's rifle length FF tube with PRI's rifle length rail . . . NOT the ARMS PEQ rail.
In other words . . . this + this; +
armalite is still around in Midlength, which is good cuz you want to use the normal rail by your gas block to install your front buis not the SPR rail cuz you want it at the right height. , I'm pretty sure it uses screws to fasten the rail to the handguard
check out these beauties!!!