For the purpose of covering my ass during a potential purchase, I'd appreciate someone bringing me up to speed on the following:

Is it possible to tell if a particular rifle (pre-ban Colt Sporter for instance) has ever been:
1. Illegally converted to select fire, & then, 2. Returned to original semi-auto configuration?

I have heard that the lower would have to be "drilled" to perform this conversion. If so, what would I look for to tell if this had ever been done?

Also, assuming that some sort of this type modification had been performed, could this receiver be made legal again? Thanks. GCF

I believe that if a rifle is in legal configuration when you perchase it, there is nothing wrong with owning it, assuming it's not stolen or wanted for evidense.

That said, I don't think a gun whose receiver is drilled is legal.  You might post this in the legal or full-auto forums, as there are knowledgible individuals in those forums who would be glad to help you.

Welcome to the site!

If it is not a registered receiver i.e. full auto, it cannot be drilled to accept the auto sear.

CIB    Northwest Arkansas/ Springdale Where you be.........?

I be in North Central, Mammmoth Spring to be exact.  I assume your in the N. West corner?

You could possibly have the holes welded closed and then you might be ok.  I'd right a letter to ATF and ask them the question.  If you're afraid to do it have the letter sent out and addressed back to a friend.

I didn't know that any receiver modifications were needed.  (This assumes an unblocked lower)  I was under the impression that just the auto parts would make an AR Full Auto.

What made me think this was true is the sensitivity that the feds have toward any semi AR having ANY auto parts.  

A semi auto FAL can have all the FA parts you want on it, just don't have a sear cut receiver.  (of course, this eliminates a place for the sear)  The feds don't say that a full auto selector in a FAL makes it a machine gun, but they do say that for an AR.  

I thought the whole reason for the sensitivity toward FA AR parts was that receiver mods were unnecessary.    

Do I understand correctly that I should be able to do a quick "hole count" / comparison w/ a known legal receiver to verify any former auto sear modifications?

Hate to get in a jam over a "good deal"!

Thanks for the feedback - GCF

I could be mistaken, but I think a regular M-16 takes a sear for which there is an extra hole in the receiver.  Hence, converting an AR-15 to M-16 sear requires an aditional drill hole.

There are also Drop-In-Auto-Sears/ Lightning Links which do not require any Reciever Mods.

Ask BISHOP.

I think AR 15.com (not the forum) has a section on what the auto parts look like. If you can't find that Bushmaster has it printed in there catalog. If you can't find an answer just go with a post ban. Stay safe. If you suspect something and you probably do for asking the question. Is a flashider/bayo lug worth it?

I'm pretty sure the auto sear hole is above the trigger assembly pin hole near the upper portion of the lower receiver.

The sear pin hole is above the selector lever. If I get a chance tomorrow, I'll post a pic of an M16 lower. If you need any more detailed info, call Ed at Gun Smoke Enterprises, a Title II manufacturer of Class 3 weapons. 863-763-1582

Once a machinegun, always a machinegun. If it was drilled for the auto-sear, you don't want it. It's obvious if it was. The hole would be above the selector switch. The hole is completely through the sides of lower reciever.

If a RDIAS or auto conector (these are classified as the machine guns, not the host gun) was used and M16 internals were installed, it can be returned to an AR15 semi-auto rifle quickly and legaly.

An AR15 won't be a full auto rifle if M16 internals are installed without the addition of an auto sear, RDIAS, or lightning link. Of course the ATF would say different. Just make sure the internals are semi-auto Ar15 internals. The bolt carrier, trigger, hammer, disconector, and selector switch are all different.

It is well within the unalienable rights enumerated in the 2nd Amendment.