View Full Version : Is it Legal to "Modernize" A full-auto M 16

February 15, 2008, 03:23 PM
I am relaying this question to the FiringLine for a friend of mine, because honestly I could not answer his question.

What is the limit, (if any at all) that you can legally modify a fully automatic m-16 (or liken machine gun). Can you have a paint job done on it, have it gun-smithed to accept modern day rails, sights, (Eotech ex), new types of titanium suppressors . . . you know "the works" with all the bells and whistles available to normal, modern semi-autos.

Is it legal at all to do this, and if it is to what extent can these kinds of modifications be made? Is there a legal limit of any kind?

(Just FYI I do not condone the idea of modifying such historical weapons in this manner but I did tell that friend of mine that there is no question on this earth about guns that the good people of the FireLine can't answer :) so mabey some out there can prove me right . . .)

February 15, 2008, 03:59 PM
No problem on any of these as long as you don't destroy the receiver or registered part (you can't replace it) and obey all laws as far as transferring it for work to be done.

February 15, 2008, 06:05 PM
Tell your freind to go for it. My M16 looks nothing like it did when I bought it.

February 15, 2008, 06:28 PM
I dont see why orifying the upper/lower receiver would have anyy effect on the laws. As long as youre not changing out parts I see no problem with getting the upper machined to accept an eOtech etc....
: D
Good luck

James K
February 15, 2008, 08:18 PM
The only areas where you might have a problem changing is with the information provided on the registration - barrel length, overall length, and caliber. The first two, as limits, don't apply to machineguns (no such thing as a "short barrelled machinegun"), but BATFE might want to be told if they are changed. I would call them before changing those areas.


February 15, 2008, 10:07 PM
Can't he change out the entire upper with a brand new one if he wants? I thought the only thing that is registered is the receiver/lower.

February 15, 2008, 11:59 PM
Can't he change out the entire upper with a brand new one if he wants? I thought the only thing that is registered is the receiver/lower.

Yes, of course, there's no restriction and no method to change what is on the registration.

February 16, 2008, 06:58 PM
On a RR M16, there is no limit to what you can do. Mostly, there is no gunsmith required. It is very easy for an end-user to replace forends, buttstocks, grips, uppers and the like. Like was suggested before, if you want an upper with threaded barrel and a flattop, just buy one! Push 2 pins and you are in business!!!!!

4V50 Gary
February 18, 2008, 11:39 PM
It's my understanding, but you may have your friend check with the ATF, so long as the lower is legally registered as a machine gun, the upper doesn't matter on the M-16.

February 19, 2008, 12:24 AM
hell if i were your friend i'd get a .22 conversion kit.
that'd be fun...

March 6, 2008, 01:31 PM
Your friend can do ANYTHING he wants to his M16. He can even put a 2" barrel on that bad boy if he wants.

If there is something that he wants done and feels better using a smith for the work, he can send it to him (the smith does not have to have an SOT) for the work. It is recommended he do so on an ATF Form 5320.5 (also know as Form 5), but it is no longer an ATF requirement. Sending an item for smithing work DOES NOT constitute a transfer.

The short of it is this. If it is a LEGALLY OWNED transferable M16 lower (the part holding the trigger and mag) he can do whatever he wishes to the upper. All styles, optics, silencers, types of barrels, accessories...

March 9, 2008, 10:32 AM
just leave it the way it is