Sportsman Guide has a used US Military Surplus Colt M16A1 Parts kit for sale. To me it's a little pricey, since it's missing a barrel, and lower receiver. It does have the fixed carrying handle, tear drop F/A, triangle fore end, and the bird cage flash suppressor. It's like the one I used in 69 in Nam. It also comes with a 30 round magazine, which we did not have. Some guys had shade tree 30 round mags, but, I never would trust my life to a jerry rigged magazine. Here's the link:
Colt M16 Parts Kit - 1578899, Tactical Rifle Acc at Sportsman's Guide
Colt M16 Parts Kit - 1578899, Tactical Rifle Acc at Sportsman's Guide