Whats the difference? This Uper reciver for LMT says i need to use a M4 barrel extension whats the difference between that and any other a4 uper reciver? Couldn't I just use any barrel? does anyone know if that thing comes with foward assist and dust cover?

A4 uppers have M4 feedramps, which require a barrel with the M4 feedramps as well.

Regular flat top uppers (A3) don't have the feedramps.

I'd say that since it says "complete" that it would come with the ejection port cover and forward assist assembly.

+1

Ref. Clearing up “M4 Feed Ramp” misinformation thread by ADCO


Bravo Company have a new model 20" gov't barreled upper with M4 barrel extension and matching upper with feedramps.

Bravo Company Manufacturing's NEW 20-inch Govt thread link

Thanks for the info. Where could I get a T- Numbered uper that is normal.

Where would I get a barrel with feed ramps? How could I tell if it has it before I order it will it say M4 Barrel or will it say has feed ramps or something?

Could I use the same bolt?

I'm sure that many Arfcom dealers could help you out. Just make sure that the barrel type matches the upper type. You can use the same bolt regardless of what type of feedramps the barrel extension has.

Quoted: A4 uppers have M4 feedramps, which require a barrel with the M4 feedramps as well.

M4Madness-

The guys over on the 10-8 forums would string you up for that statement.
Just so you know, there is no such thing as an A4 receiver with M4 feedramps.
A flattop receiver with M4 feedramps IS an M4 receiver.

Fun with designations:
M16A1: Safe, Semi, Auto with a carry handle
M16A2: Safe, Semi, Burst with a carry handle and new style rear sight
M16A3: Safe, Semi, Auto with a flattop
M16A4: Safe, Semi, Burst with a flattop
M4: Safe Semi, Burst with a flattop and feedramps
M4A1: Safe, Semi, Auto with a flattop and feedramps

For clarity, we should split the two flattop receivers into either A4 or M4 and call it done.

Randall