G3 Kit Build Questions

[zackdamundo]

I have ordered and will be receiving a pre-bent receiver, parts kit and barrel for a G3 from my local FFL and have a few questions.

First, there will still be some welding required: for the trunnion, possibly a Pic rail (haven't decided) and from what I understand a self in the trigger group.

Considering a few routes: 1) rent TIG welding equipment, learn to weld, learn what I can from the internet and hope for the best. 2) find somebody local who is willing to show me how to do this (I don't own any welding supplies and don't know how to weld). 3) find somebody local who can do the build. 4) ship everything off somewhere to have it professionally built (least favorite option of these).

I know G3/CETME rifles are a little more complicated, so just thought it worth asking around first. I recently built a different kind of rifle, enjoyed the process, and am looking for more challenge. Is there anyone here who has experience with these, any pointers? Anything I need to know from a legal standpoint just so I stay on the right side of the law?

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[edzz]

Find a local school that has an intro to welding class. Tig welding isn't hard however having a mentor that can provide immediate feedback will be a lot better than wasting a lot of gas and tungsten.

 

[gmerkt]

I will send a message to a friend of mine who built two of these about 15-20 years ago. I may be able to get some tips from him about doing this. If you have a pre-formed receiver, you are ahead. He had to deal with a receiver flat and a jig to do the bending himself. Due to his ongoing desire for anonymity, I can only try to get this second hand.

 

[zackdamundo]

Find a local school that has an intro to welding class. Tig welding isn't hard however having a mentor that can provide immediate feedback will be a lot better than wasting a lot of gas and tungsten.

Community college route is a good idea, had not crossed my mind. Good life skill to learn.

 

[JuglansRegia]

Tig welding isn't difficult but Tig welding sheet metal is. Finding someone with the right equipment and skills would be money well spent. Unless you plan on doing a bunch of them then learning the skill yourself might make sence.

 

[edzz]

Tig welding isn't difficult but Tig welding sheet metal is. Finding someone with the right equipment and skills would be money well spent. Unless you plan on doing a bunch of them then learning the skill yourself might make sence.

If you decide to do it yourself practice a lot on scrap before touching your receiver. What JuglansRegia said about welding sheet metal is right on and will make or break a successful build.

Google "maker space" for your area Past Lives is one of the locations that google shows in portland along with a few others.

Look at their web page, maker spaces provide a wide assortment of equipment with knowledgeable mentoring. A maker space would be a lot easer for you than trying to rent and wiring up a 220 outlet.

 

[zackdamundo]

The maker space idea is solid too. Definitely would look to do a lot of practice before hand.

 

[gmerkt]

Here is what my pal messaged back to me about when he did his:

In today's reality, I would not trust anyone except MAYBE family and maybe not. There are not many friends who are and have been like you, a close friend for 61 years. So in my opinion, I choose to do the welding myself. Use the internet for welding instructions and local for supplies. I was 50 yo when I built mine, which was not old enough for me. The trick to welding is knowledge, experience, patience and patience. I didn't have the last two. Okay, when you weld the receiver to the trunion clean everything with alcohol, be accurate on measurements, this is a one try effort. My opinion, it is never OK for me to butcher a receiver, but that is me. If you are successful attaching the receiver to the trunion, the next important thing is to weld the sight to the receiver. I should say that my rifle was new when they cut the receiver and I have the rear sight. I carefully cut it off the rear of the receiver, I aligned it on the new receiver with a jig that I made from two pieces of scrap wood and two metal all thread, my sight was placed on the new receiver at exactly the same as measured by a small micrometer, but there are better ways. Scribe lines around the sight before it is removed from the old receiver for close measure. If you are close with the sight , the L to R is set at the range. The trigger pack fits on the bottom of the receiver and the bolt carrier fits the receiver. The bolt carrier needs to fit with minimum effort to move in the receiver. Just a thought, I used a MIG welder instead of a TIG, I own a MIG. The cocking tube had to be removed and refit to the new assy. I didn't mention that in my rifle, the barrel was attached to the receiver via the trunnion, the old receiver was removed from the trunnion and barrel and the new receiver was welded on with six 1/4 in holes. 2 articles attached. Answering questions is best. Man that is a long time ago
G3 Armorer's manual:

http://pdf.textfiles.com/manuals/FIREARMS/hk_g3.pdf

HK91/G3/CETME clone build

www.pirate4x4.com

There are other reference you can find on Google.

The legal stuff, that is on you.

 

[zackdamundo]

Here is what my pal messaged back to me about when he did his:

In today's reality, I would not trust anyone except MAYBE family and maybe not. There are not many friends who are and have been like you, a close friend for 61 years. So in my opinion, I choose to do the welding myself. Use the internet for welding instructions and local for supplies. I was 50 yo when I built mine, which was not old enough for me. The trick to welding is knowledge, experience, patience and patience. I didn't have the last two. Okay, when you weld the receiver to the trunion clean everything with alcohol, be accurate on measurements, this is a one try effort. My opinion, it is never OK for me to butcher a receiver, but that is me. If you are successful attaching the receiver to the trunion, the next important thing is to weld the sight to the receiver. I should say that my rifle was new when they cut the receiver and I have the rear sight. I carefully cut it off the rear of the receiver, I aligned it on the new receiver with a jig that I made from two pieces of scrap wood and two metal all thread, my sight was placed on the new receiver at exactly the same as measured by a small micrometer, but there are better ways. Scribe lines around the sight before it is removed from the old receiver for close measure. If you are close with the sight , the L to R is set at the range. The trigger pack fits on the bottom of the receiver and the bolt carrier fits the receiver. The bolt carrier needs to fit with minimum effort to move in the receiver. Just a thought, I used a MIG welder instead of a TIG, I own a MIG. The cocking tube had to be removed and refit to the new assy. I didn't mention that in my rifle, the barrel was attached to the receiver via the trunnion, the old receiver was removed from the trunnion and barrel and the new receiver was welded on with six 1/4 in holes. 2 articles attached. Answering questions is best. Man that is a long time ago
G3 Armorer's manual:

http://pdf.textfiles.com/manuals/FIREARMS/hk_g3.pdf

HK91/G3/CETME clone build

www.pirate4x4.com

There are other reference you can find on Google.

The legal stuff, that is on you.

Very helpful, thanks for following up there. And please pass along my thanks to your friend.

 

[JuglansRegia]

The tig welding done on factory HK rifles and mp5 type receivers is either done by someone with years of experience or even by machine all specifically set up for that one task. If you want your welds to look anything like that, you will need the right equipment set up the right way and then lots of practice which equals experience. Sheet metal is pretty cheap to acquire for practice but I would suspect HK receivers are made out of something a little better than standard mild steel.

 

[Val1884]

Need a nice Tig to do these right. Around 75 a an a pedal an it's a hour build. You'll need a press for the barrel assembly an feeler gauges to set everything right. Laser level makes doing sight alignment a breeze for getting rear base tacked straight before welding. I've seen several mig'd but they don't look right.

 

[zackdamundo]

This has been a really helpful thread. I also found this on ARS website, which really shows the detail that goes into everything:

HK Tutorial: Build a JLD PTR-91 HK Clone – Arizona Response Systems

www.arizonaresponsesystems.com

I'd still love to learn to TIG weld in the future, but it's pretty clear this isn't the project for that.