A buddy of mine just called to tell me of an interesting mistke he made while trying to smooth out the trigger on his SAR: he smoothed too much of the left side of the hammer, thus creating a situation where it is NOT FULL AUTO, but a round is fired not just when the trigger is pulled, but since the sear no longer catches the hammer due to over-filing, a round is discharged upon RELEASING the trigger as well.  We can all visualize how fast this could empty a magazine!  He has already replaced the hammer he fouled up with a spare he had, but is what was created really in infraction?  A very reputable gun dealer in my area a year ago showed me an M14 he had in stock that he bought with this same config., and though he was planning to have it "fixed" prior to sale, he did call the ATF regarding this and he sys that they said that it was NOT an infraction, merely highly irregular.  Given that this accident did NOT make a fully automatic rifle, but merely a condition which will discharge a round upon BOTH actions of the trigger, has he indeed made an illegal rifle, or merely an anomoly that could be real damned fun to shoot?  Does anyone know for SURE?  I guess it's moot since he already replaced the hammer, but I found it an interesting condition.  Discuss.

Unless someone else has a better answer, the only way to be totally safe is to get approval in writing from this guy:

Branch Chief
Firearms Technology Branch
Bureau of Alcohol, Tobacco and Firearms
650 Massachusetts Ave., N.W.
Washington, DC 20226

Uh huh.

That's ok. The BATF has CYA people working their gun testing lab that have been quoted as saying they were proud of the convictions they helped get by using their knowledge of how to get legal unmodified semi-autos to fire in bursts.

I didn't mean you should tell them about your buddy's trigger. You can ask the ATF about a hypothetical trigger, and they will answer. As a machine-gun designer (but not manufacturer), I have discussed several hypothetical machine-guns with the ATF.

(If they ask for a "sample" of such a hypothetical item, I would be inclined not to send one.)

The thing is, even if the trigger is legal, it would be helpful to have an ATF-approval letter to carry with the gun, in case it's ever questioned by a local LEO.

from what i can tell your hypothetical trigger is  to make the gun go bang on the pull then fire another on the release? that would be more then one round per pull of the trigger and would then hence forth be a machine gun in the eyes of the ATF

All very interesting indeed.  I'm glad he trashed the mistake.  Nothing is worth incurring the wrath of the ATF!

What this hypothetical trigger modification does  is turn a safe, legal rifle into an unsafe and probably illegal one.  I would put fresh lockwork in it and toss the other parts right away.

Yes, that is possibly not only an illegal situation, but a severely [b]dangerous[/b] one as well!

Thankfully, your friend has rectified the situation.

Friends don't let friends mess around with AK trigger/sear assemblies!

Eric The(Leary)Hun[>]:)]

Yep!