What happens if a full-auto sear breaks on a gun?

If I had such a gun (which I do not), and if the sear may be succeptible to breakage, as well as any other parts, I would have a few spare parts on hand, just in case they break.

I know nothing about automatic weapons, so I am only telling what I would do IF I had such a weapon and IF the certain parts were prone to somehow wearing or breaking. It would seem that it might just make the gun a semi-automatic, however I do not know that for certain.

A machine-gun guy would need to answer this.

if i understand correctly it depends on which part of the gun is registered

if you have a registered receiver like an M-16, then the sears are just another replaceable part

but if you have something like a registered auto sear or a lightning link, and that breaks, i think you are SOL

but if you have something like a registered auto sear or a lightning link, and that breaks, i think you are SOL

Click to expand...

I'm not the authority on the matter, but I thought you could have the old sear destroyed and a new one manufactured, similar to the repair process of a suppressor where each baffle needs to be destroyed before new ones can be made and replaced?

TheGewehrGuy said:

Are you SOL?

How likely is it to happen anyway?

Is it an easy fix? As long as the serial number is there?


I know full-auto guns are great investment (legally), but how good is an investment if it can break fairly easily?


I am thinking about someday buying an MP-5 with a registered sear, and swapping the lower with a (SBR registered or legal) upper, but if anything happens to that sear I don't want to be SOL.

Click to expand...

You are officially SOL.

TenMillimaster said:

I'm not the authority on the matter, but I thought you could have the old sear destroyed and a new one manufactured, similar to the repair process of a suppressor where each baffle needs to be destroyed before new ones can be made and replaced?

Click to expand...

If you find the part of federal law that allows it, post it. I've seen this discussed before and nobody ever expounds upon it after the first post. The same also applies to silencers. If you blow the tube, you are SOL.

You can replace anything but the registered part. So if you have a converted gun where the sear itself is the registered machine gun, you're (legally) screwed if it breaks.

Hold on... we just had a discussion on this and "S(imply) Out of Luck" is not the correct answer.

The original question is on Drop In Auto Sears (DIAS) or "Lightning Links", but the same would apply to registered receivers.

When an item is worth over $10,000, it is worth fixing if it breaks. Especially if no new one can be created.

We have some pretty seriously talented machinists and welders in this country, and some of them are employed by SOT2 types and gunsmiths who can service full-auto registered receivers and DIASs. Either one of those would have to be substantively destroyed before it wasn't worth paying a very expensive professional to make it like-new.

You can weld up and grind back to spec. worn surfaces or egged-out holes. A welder can weld cracks and breaks, if he/she really know what they're doing.

Re-welding a DEWAT Garand receiver is probably not worth the expense of doing correctly (so many weren't done correctly). But a registered receiver or registered auto-sear is a pretty valuable part. Spending a few thousand to have serious repairs made is probably money worth spending.

Now, if it falls into a wood chipper or is otherwise disintegrated...yeah, then you're out of luck. That's a really good reason to have insurance.

Sam has this one correct. I will gladly pay both transfer taxes to take one of the "broke/SOL" MG's off of anybody's hands.

GoingQuiet said:

TenMillimaster said:

I'm not the authority on the matter, but I thought you could have the old sear destroyed and a new one manufactured, similar to the repair process of a suppressor where each baffle needs to be destroyed before new ones can be made and replaced?

Click to expand...

If you find the part of federal law that allows it, post it. I've seen this discussed before and nobody ever expounds upon it after the first post. The same also applies to silencers. If you blow the tube, you are SOL.

Click to expand...

As far as there being anything in federal law allowing it, I'll agree that there isn't. And per the ATF's own handbook

"7.5.4 May machinegun receivers be manufactured and used as replacement parts for
machineguns lawfully registered and possessed prior to May 19, 1986?

As previously stated, 18 U.S.C. 922(o) generally makes it unlawful to possess or transfer any machinegun, including a
machinegun frame or receiver, manufactured after May 18, 1986.

Exceptions are provided for weapons produced by a qualified manufacturer for sale to government entities, as dealer sales samples, or for
exportation.

There is no exception allowing for the lawful production, transfer, possession, or use of a
post-May 18, 1986 machinegun receiver as a replacement receiver on a weapon produced prior to May
19, 1986."

http://www.atf.gov/publications/download/p/atf-p-5320-8/atf-p-5320-8-chapter-7.pdf

But saying that, I know and have personally see an example of one, that there are some Olympic Arms receivers that have had registered serial numbers put on new receivers and the original receiver destroyed. Word is this was originally for a defect in the casting material, but was expanded to "out of spec" receivers before the ATF put the end to it. I've also seen some pretty convincing evidence, though I admit its all photographic, that Colt has done the same for some "special people", newer gen receivers with features that didn't exist before the registry closed with old serial numbers on them.

In no way am I saying that you'd be able to get either to do such things now, just that they've been done in the past. Olympic Arms apparently was given a stern talking to and the ATF left it at that.

Sam1911 said:

Hold on... we just had a discussion on this and "S(imply) Out of Luck" is not the correct answer.

The original question is on Drop In Auto Sears (DIAS) or "Lightning Links", but the same would apply to registered receivers.

When an item is worth over $10,000, it is worth fixing if it breaks. Especially if no new one can be created.

We have some pretty seriously talented machinists and welders in this country, and some of them are employed by SOT2 types and gunsmiths who can service full-auto registered receivers and DIASs. Either one of those would have to be substantively destroyed before it wasn't worth paying a very expensive professional to make it like-new.

You can weld up and grind back to spec. worn surfaces or egged-out holes. A welder can weld cracks and breaks, if he/she really know what they're doing.

Re-welding a DEWAT Garand receiver is probably not worth the expense of doing correctly (so many weren't done correctly). But a registered receiver or registered auto-sear is a pretty valuable part. Spending a few thousand to have serious repairs made is probably money worth spending.

Now, if it falls into a wood chipper or is otherwise disintegrated...yeah, then you're out of luck. That's a really good reason to have insurance.

Click to expand...

This is both right and wrong.

YES - a broken sear can be re-welded in terms of technical ability by a good metalworker.

NO - the ATF has indicated to myself and other SOT's that re-welding a broken sear constitutes new manufacture. Just like re-welding a demilled parts kit constitutes making a new gun.

the ATF has indicated to myself and other SOT's that re-welding a broken sear constitutes new manufacture. Just like re-welding a demilled parts kit constitutes making a new gun.

Click to expand...

Hmmm... can you explain exactly how far this ruling extends? Is there some line where they consider it to be "destroyed" or "nonfunctional" and then it cannot be brought back? If they're going to prohibit something, they'll need to be somewhat specific about what does or does not fall within the prohibited category.

Broken right through is trash, but cracked nearly in half is salvageable?

Sam1911 said:

Hmmm... can you explain exactly how far this ruling extends? Is there some line where they consider it to be "destroyed" or "nonfunctional" and then it cannot be brought back? If they're going to prohibit something, they'll need to be somewhat specific about what does or does not fall within the prohibited category.

Broken right through is trash, but cracked nearly in half is salvageable?

Click to expand...

Broken = trashed.

If something is CRACKED - it can be re-welded.

Well, thanks for the clarification!

Does this only apply to autosears, or would a registered receiver or trigger pack or other part also have a "magic line" where it is too broken to legally save?

And, not to beg the question, but how is this enforced? An autosear with a weld repair for a crack "nearly through" would look a lot like an autosear with a weld repair for a crack "right through". I presume a gunsmith doing this would need to be caught at it in the act. Or do they have a standard by which evidence of a too-extensive repair, if found, can lead to forfeiture and charges filed?

Are there serial numbers on these DIAS or lightning link? Otherwise how in the world would they know if yours is registered?

Click to expand...

Yup. All Title II items are serialized.

An autosear with a weld repair for a crack "nearly through" would look a lot like an autosear with a weld repair for a crack "right through".

Click to expand...

Done properly either would look like a new part, not one that had been fixed.

TheGewehrGuy said:

Have you EVER heard of a DIAS or lightning link breaking? If its a 1-in-a-million chance, I would never even worry about it, and these original question would be pointless.

Click to expand...

All metal mechanical parts wear from friction during use. All sears will constantly have metal being removed from them as they operate, even if they don't crack or break.
Eventually that lost metal causes them to be so out of spec that new metal will need to be added or they will start to malfunction, and are more likely to break because less metal makes the component weaker.
When it is an object that will be mechanically operated for decades, and pass from one user to another it is not a matter of if but when it will need more metal added to it to keep it working of keep it from breaking.


It might be smart to add new metal to such a registered component on occasion just to maintain original specs and dimensions so a repair is not actually necessary.

I also don't see how the ATF can tell people they cannot repair their existing registered product if something breaks during normal use. That does not pass the legal smell test, and if some do hold such a view a lawsuit (obviously with someone willing to fund one) should straighten it out. I would want to see a letter stating as much, because it runs contrary to many other parts of federal law.
Of course such a lawsuit would cost more than a new registered part, so maybe the ATF can screw with the little guy because with the finite market of registered machinegun owners the agency does not have to legally take on the firearm community as a whole to screw them over. They are a little segment that can be manipulated and have a small voice (although several of them have decent funds to be purchasing such toys, which means they could afford decent attorneys).
But a lawsuit on principal should be effective if the ATF kept someone from repairing or restoring their legally registered title 2 firearm to the same dimensions it was registered.

Zoogster said:

TheGewehrGuy said:

I also don't see how the ATF can tell people they cannot repair their existing registered product if something breaks during normal use. That does not pass the legal smell test, and if some do hold such a view a lawsuit (obviously with someone willing to fund one) should straighten it out. I would want to see a letter stating as much, because it runs contrary to many other parts of federal law.

Click to expand...

Just because it doesn't pass a smell test doesn't mean it won't happen. Keep in mind the BATFE is the most unconstitutional agency in existence and they rarely get told no (although that seems to be changing... Gunwalker anyone?).