shelf in trigger box

[pyroclayman]

I'm pretty good with silver solder or Tig, but it looks to be pain to get any kind of weld way down in these grip frames.

Is it legal to use high temp silver solder for the shelf in the grip frame? Hope so.

Thanks,

P

[Otis61]

I just spot welded with an arc welder. Worked fine.

[vista461]

I drilled a hole in each side of the housing and plug welded it

[pyroclayman]

I had not thought of either of those options. Thanks!

Hmm, have a copper tonged spotwelder, that would work huh. Missed the obvious.

'Thanks again,

P

[M1 Tanker]

This is an ATF letter on HK trigger packs from investment grade firearms.

Department of the Treasury

Bureau of Alcohol, Tobacco, and Firearms

Washington, DC 20226

Sept 28, 2001



Mr. Jason Cotter

Mountain Home, AR 72653



Dear Mr. Cotter

This is in reply to your letter in which you have requested proper procedure for modifying a Heckler and Koch G-3 machinegun trigger, into a semiautomatic trigger.

To properly convert a G-3 machinegun trigger into a semiautomatic only trigger there are several modifications needed. The modifications are listed as follows:

1. Remove the automatic sear.

2. Grind off the automatic sear notch from the face of the hammer

3. Cut away the front corner of the trigger housing where the automatic sear is mounted, .410-inch from the bottom and .540 inch from the front towards the rear.

4. A new hole has to be drilled to accommodate the trigger spring. The hole dimension is .200 inch drill that hole .165 inch from the front of the new corner and .250 from the bottom of the new corner. These dimensions are for the center of the hole.

5. The trigger spring should be replaced with a semiautomatic trigger spring but the G-3 trigger spring will work.

6. The trigger over travel stop has to be moved towards the rear tang of the trigger .150-inch

-2-

Mr. Jason Cotter

7. It will also be necessary to modify the trigger housing. Modify the housing by cutting off the tabs for the front assembly pin. Then adjust the fit of the housing into the receiver.

Title 26, United States code, Chapter 53, section 5845 (b), defines the term machinegun as any weapon which shoots, is designed to shoot, or can be readily restored to shoot, automatically more than one shot without manual reloading with a single function of the trigger. The term shall also include the frame or receiver of any such weapon, any part designed and intended solely and exclusively, or combination of parts from which a machinegun can be assembled if such parts are in possession or under control of a person.

If you do not properly modify the G-3 machinegun trigger pack and install it in your semi automatic rifle, and that weapon fires more than one shot automatically with a single function of the trigger, you would be in possession of an unregistered machinegun.

We trust that the foregoing has been responsive to your inquiry. If we can be of any further assistance, please contact us.



Sincerely yours,

Curtis Bartlett

Chief Firearms Technology Branch

[tomoshenko]

7. It will also be necessary to modify the trigger housing. Modify the housing by cutting off the tabs for the front assembly pin. Then adjust the fit of the housing into the receiver.

Reading this, I come away with two things:

They don't want the tabs on the housing (So how are clip and pins okay???).

They don't care how you fit in the trigger housing shelf that rests on the receiver shelf. I take this to mean brazing,tig,mig whatever ya got is okay.

Any other thoughts or opinions?

[Otis61]

Thats what it looks like the letter says to me.

[texlurch]

I "think" where they say that the housing will need to modified by clipping the ears, is to fit the shelf. But I have seen far too many with fake pins to believe it is a problem.

It is just like putting in the paddle mag release; you cannot drill over a 1/8th hole, and only from one side, and it has to be welded shut.

Think of it like the third hole on an AK receiver. As long as the hole in the receiver doesn't exist, you're golden.

[brewskzilla]

You guys are geniuses. M1, I'll just bet you didn't even have to look for that letter, did you? This place really has it's $h!t together. By the way, silver solder may not be sturdy enough to suit your needs. It's somewhat pliable, even completely cooled, and that could cause problems, depending on exactly what you're using it for.

I'll shut up, now, as I am by far not the most educated on this topic. I use solder for electronics. THEREFORE, my opinion is relatively moot.

[ocharry]

i used silver solder on mine,,and like you i couldn't get the tig torch into the housing

the silver if done right is 100% bottom and sides,,,,i haven't had any trouble with it nor do i expect to

my .02

ocharry

[pyroclayman]

i used silver solder on mine,,and like you i couldn't get the tig torch into the housing

the silver if done right is 100% bottom and sides,,,,i haven't had any trouble with it nor do i expect to

my .02

ocharry
Yea, well high temp silver solder is pretty hard and tough stuff. Now mine is both spotwelded and silver solderd. Think it will hold.

P

[M1 Tanker]

All mine are welded...weld it from the outside and grind it flush. Hell it would be easy to braze on too. I've used hi temp silver solder on muzzle brakes back in the day when we had to no choice without one ever coming loose. We also put on rear sights with it at work. I think it'll hold just fine.

And yes Brew, I knew right were it was :)

As to the clipped and pinned thing, no I don't believe it an issue at all.

[tomoshenko]

All mine are welded...weld it from the outside and grind it flush. Hell it would be easy to braze on too. I've used hi temp silver solder on muzzle brakes back in the day when we had to no choice without one ever coming loose. We also put on rear sights with it at work. I think it'll hold just fine.

And yes Brew, I knew right were it was :)

As to the clipped and pinned thing, no I don't believe it an issue at all.

M1,
Could you elaborate on your "weld from the outside" procedure for us TIG hacks. Thanks much, Tomo

[M1 Tanker]

8465

[tomoshenko]

8465

There in lies my misunderstanding! I was talking about the shelf in the grip frame that contacts SA shelf on the receiver. Sorry for being unclear with my question.

[pyroclayman]

There in lies my misunderstanding! I was talking about the shelf in the grip frame that contacts SA shelf on the receiver. Sorry for being unclear with my question.

As was I. I should probably apologise for being sloppy with the nomenclature.

As for acutal trigger boxes, I've been lazy and avoided the complicated looking (to me) changes that need to be made to convert to semi auto.

1st G3 parts kit came with a proffesionaly done already converted triggerbox.

Second, I just bought PTR strange aluminum semi trigger box. This worked to keep it simple. All that was left to do was swap the internals, and then convert the grip frame, which was no biggie.

P

[M1 Tanker]

Ahhh, the grip frame, gotcha. Mine is JB welded in.

8466

[pyroclayman]

Ahhh, the grip frame, gotcha. Mine is JB welded in.

8466

Hmm. I would have thought that JB for this would not satisfy BATF, but I'm rather new to all this, and certainly could be wrong.

[rustypirate]

The only thing here that must satisfy the BATFE is that the grip frame must be modified to fit the receiver shelf, and not the other way around.

the method of modification is not specified.

[M1 Tanker]

Big50 did mine...and I'm pretty sure he knows what he is doing.

[ocharry]

yep grip frame is what i was talking about too,,,shelf is silvered in place,,,as for the trigger box,,tig welded just like M1 has shown


ocharry

[trenches]

I welded the small piece of metal in the trigger box like M1 did. I also welded the shelf to the receiver. I put the welds on the bottom of the shelf. I wasn't even going to try getting the tig torch in between the shelf and the receiver. I have gone into some tight spaces like re-attaching the locking tab in the rear of the PPS43. That was tight. Also the area in the channel where the charging handle rides in my semi Mg-42 at the rear of the ratchet plate.. That was a challenge.

[Rocky]

I use hydraulic fittings up to 5000 psi that are siver soldered and never seen one fail , that stuff is very tough

Rocky