If you drill through both sides, it creates a machinegun, and the ATF has rule that once a machinegun, always a machinegun.
So don't drill completely through the far side of the shelf, and then weld up the closer side after the pin is installed and you are golden.

ok so i read threw and kind of understand this... what about the Vector clones that have the 3 position selectors and are set up for a sear?  i keep hearing about them and am going to look at a V51 SBR that has 3 positions and the selector goes threw all of them.... or is that wrong and waiting for the ATF to see it?

Can someone point out the ATFs position on this hole drilling in NFA law please, my BS scanner is reeling. It makes no since, i mean the same would go to anything else, what if I driped and tapped a Remington 700 receiver for a scope mount, I drilled holes in a receiver and didn't weld them....

Ok? the logical argument is that only pertains to semi-auto firearms, what about people who mill holes or skeltonize their magwells on ar-15's... they drill holes and don't weld them over, into a semi-auto receiver. Does that also mean it's a machine gun? I just have a hard time believing cosmetic/functional changes such as adding a flapper mag release that has absolutely nothing to do with F/A parts or pin locations could be construed as illegally creating a machine gun.

It pertains as to the same thing for drilling the 3rd hole for the sear in an AR15. Since the AR15/M16 Fire contol group actually mounts into the receiver, there are 2 holes (trigger & hammer pins) and 3 if its a machine gun (sear). The H&Ks have the removable trigger pack in which the fire control mounts into and is separate from the receiver. With the 2nd hole on a H&K roller lock platform (under magazine catch), it allows the swing down pack to be theoretically installed. Once a swing-down pack can be installed it can accept full auto fire control group parts. This is what the ATF doesn't want. Since the semi auto shelf protrudes off the back of the magwell it blocks the F/A pack from being installed unless modified to a semi auto only configuration. Drilling the Mag well on the AR15 has nothing to do with being a machine gun since that has no effect on the fire control group it can accept because the sear is located above the selector.

In terms of the paddle release, the assembly uses the 2nd hole as a guide. Once the hole is drilled it is viewed as a machine gun in the eyes of the ATF no matter what. Since drilling one side and then putting a small indent in the 2nd side doesn't pierce the metal completely of the receiver, it is not considered completing the 2nd hole in the receiver, therefore is it not a machine gun.

Ok so there no need to weld over the partially drilled mag release hole; I understand the workings of an ar, but i wasn't sure how adding a mag release hole also allowed a full auto sear to be added. I believe thats what your saying, that the flapper mag release lever hole is also used for a sear or something, not just the mag release. Which makes more since to criminalize.

So what about the MKE guns? hey have the 3rd hole.

ATF like there to be a lot of redundancy in so far as modifying guns to be not full auto but when it comes down to it there is usually one single modification that is ALWAYS a no-no. With AR's it's the 3rd hole, with HK it's the front pivot; same-same. The reason being that ATF feels that with the front pivot hole it is exponentially easier to just drop on a new f/a trigger assembly. Now, understand that we're only talking about the receiver mods themselves here and not the other parts. Say you modify a semi trigger pack to accept a registered auto sear but you don't have a sear to go in it, or if you have a sear and 2 modified trigger packs. In that case you now own an unregistered machine gun as well. The rules are arbitrary and asinine, but for now those are the rules.

As far as the MKE guns are concerned the first thing that needs to be pointed out is that they DO NOT have a usable third hole from the factory. ATF has issued a letter to MKE clearly explaining their view of their guns and the process that is used to make them. BATF does, on occasion, show a glimmer of intelligence and it shows in this letter. They acknowledge that these guns came off of an assembly line originally built to make machine guns and to modify their dies and processes to not make the front hole in the stamping would be cost prohibitive. They find that even though this hole is present originally, so long as it is made inoperable during the course of original manufacture it is not a MG. Some of the very early MKE guns had plugs installed into the holes and some of those plugs did fall out. This could present a bad situation for an uneducated owner and I understand that MKE is fixing the issue. The later generation of guns has this plug welded and will not be a problem in the future. It is worth noting that other manufacturers have also produced semi, civilian legal guns from flats that had the front hole originally including JLD and I believe even HK. Most people are unaware of this because of the larger shelf used during the manufacture of these guns.

We get these questions at least 3 times a day.
I put together a quick / simple guide on our website: http://www.hkparts.net/shop/pc/Trigger-Housings-Explained-d26.htm

Not too detailed, but seems to answer most everyone's questions.

Josh
HKParts.net

The process of "pinning" an HK-type trigger housing that has been "clipped" to make it semiautomatic seems to me to be analogous to installing one of those fake selector switches on an M1A. Yes, it's cosmetic only and has no effect on function. But since (in both cases) what you end up with is a gun that is externally identical to a machine gun, it may draw some unwelcome attention from law enforcement or from busybody interlopers. I for one don't want this type of attention.

There is a block in the rec like the colts you can't put a full auto bolt in the mke so a full auto pack does nothing in fact it will not even do semi auto

MPfiveengineer:
Could you please repost the three photos you attached to your "What does the clipped and pinned mean?" post from way back when in a different format? Clicking on the attachments just gets me to a blank ImageShack screen with no instructions for downloading the attachments (I did register with Image Shack). I would greatly appreciate it.

OP was in 2006.

OPer has not logged in since 2011.

the Trigger packs are all identical. the only difference Ive seen is the Ejector. CETME, MP-5, G-3(91), 93, and the rest.  There is a step-by step of the clipping and pinning process over on Weaponsguild with pictures.

They are not identical at all. There are a lot of common parts, but the SEF and AMBI packs differ. The axle hole for the Ambi pack comes in .550 and the SEF is .395. The ambi packs use a catch arm system as a detent system to keep the selector in position and not the grip housing. Burst packs have almost nothing that work in a SEF pack. Except for the axle pins, ejector & spring, Selector catch arm & spring, and primary sear spring. Ambi housings need a ambi pack to work (after it has been modified to semi auto)





 

I meant in Physical Size of the box itself, I havent played around with them too much so i didnt know the SEF and Abi axels were differently sized.  I've been haunting Weaponeer HKPro, and Weaponsguild, and have seen people using G3 boxes in Cetme, MP5 boxes in G-3 builds ect.

The pack itself is the same size and either will work on any HK 9X platform, so it is modular in that sense.  But SEF packs can only work with SEF housings & selectors. Ambi packs only with Ambi housings and selectors. All that is then needed is proper ejector and hammer spring



 

Photo links in the OP are broken.

And all this time I thought it was what you did when your done having kids.

So, I spent $34 and bought a non C&P HK trigger housing for use on my PTR-93. I decided that for $34, it's worth giving it a shot. I have a Dremel, I have hand files, and I had time on my hands, so why not? Turns out, it was a pretty easy, if not time-consuming process.

I used the trigger housing that came with the rifle as a pattern, and I matched it as closely as I could. When I was getting close to being done, I switched from the Dremel to hand files to allow much slighter adjustments, and this turned out to be the key to a nice, tight fit with zero wiggle. It now feels far more firm and solid than the one that came with the rifle.

The only thing I have left to do is put in a pin, epoxy it into place, and then clip them. I have some extra HK pins coming in the mail and should arrive this week. I will then complete the process, and to outward appearances, this rifle will look like a proper H&K.

I'm pretty confident that anyone with the right tools, some time, and most importantly, some patience could pull this off easily enough.

Here is a photo of the finished project. I didn't take photos while I was doing it because I wasn't sure it was going to be successful, and also because I was more interested in just doing it right than taking photos along the way. As I just bought an Omega OM9, there's a good chance I'll be doing this again. When/if I do, I will definitely get photos of the process (although, to be fair, there are lots of photos already out there of this process).

Does anyone have pics comparing semi-auto parts to FA parts?

More to my point,  there's no way this could be made full auto, right?

Attached File