I have a 1903, and need some info on a part. I am looking for the clip or retainer that the upper handguard slips into, towards the rear. The upper handguard, is fit so that it slips in and under some sort of ring, (much like an M1 Carbine) then as it is layed down into place atop the barrel, the forearm retainer slips down from the muzzle, past a keeper clip, and it tightened down, holding it in place. I looked at schematics but can't find this part, it secures the rear-most edge of the upper handguard. Any help out there please!!