I borrowed my brother's account as my phone won't let me get one myself. I recently inherited his Bushmaster AR15 from when he worked maritime security after the Cole was bombed. Long story short, he has it set up with standard Bushmaster M4 handguards but with a full length rail on the bottom screwed to the hand guard and a CAA tri rail screwed to the top. He said he outfitted it this way to keep weight down for packing it up and down in the navy vessels, since quad rails added quite alot back then. I know that it is very accurate as it stands all it has shot in the past 7 years or so is varmints out to 200yds or so. I want a Vert handgrip, bi-pod and light on it. Is there any issue with just leaving it as is and adding those? I think he had a light on the top tri rail, and a bi pod on the bottom when it was his duty rifle. With the proliferation of the quad rail, is there any major issues I should be aware of as it is set up that I would NEED a quad rail for? Thanks.