the usgi bipod is a non-starter anyway, unless you're building a m14a1e1 or something like that- what happens is that it clamps on to the gas assembly, and that clamps on to the barrel, and interferes with the barrel harmonics- the bayonet you need is an m6- if you want a FUNCTIONAL bipod, you have to remove a rivet or drill a hole, and attach a harris, which are available almost everywhere