I was looking at doing one when I did my 33K build and got sidetracked.  Well I was on a list for a 10mm MP5 and that’s happening this week so let’s get the fotay started!

Neat. In on this sweet build

I always wanted to do one up but never got around to it

Good luck!!

Also in and looking forward to this.

Some progress.

The non LSC/PTR flats are shit.

Lookin good

That fixture is really nice

I am working on a second vid for the fixture-  It has some flaws.  

Here is the first one when I put a real HK91 in it.

I bought the same HK welding jig from gunbroker user Beltfeed2 about a year ago and the jig I received had a shit-ton of problems..  I tested it with probably half a dozen german guns and none of them lined up right, same as shown in your video as many of the jig parts have significant dimensional issues.

I spent a bunch of time taking measurements for Beltfeed and he promised  to correct the issues and get me new parts which he never did.  Eventually he just stopped responding to my inquires and never sent a single replacement part, leaving me with a worthless out of spec jig.

I made a bunch of changes to try and get it all straight but there is still some work to go as I will need to make a new center trunnion support as mine is just too low (compared to the rear receiver and barrel crown holders) which would result in welding the barrel/trunnion in crooked if you used it as-is.

If you don't have the patience to fix a bunch of stuff yourself, my advice is to stay away from that seller and his jigs while they look nice and he talks a big game the reality is that they are garbage.

Could you post some pics?  That's terribly disappointing.

Sure,  here are just some of the issue I documented and sent to the seller.

First off the two end pieces of the jig that hold the two horizontal bars are not at the same height so the whole jig "sloped" to one side.

Attached File


The center trunnion support was off (too low), so if you had the rear of the receiver in the end plate, and the trunnion in the center support jig, the barrel was pointing down.  If you used the jig "as is" the barrel and trunnion would not be straight in the receiver.

Notice in the pic below (red arrow) the only way a factory HK93 fit the barrel crown support, the receiver end support, and the trunnion support was to remove the trunnion clamp so the trunnion support could slide upwards.

Attached File


When the receiver was fixtured to the receiver end support plate and the trunnion support was clamped down this is how the barrel aligned with the crown support jig. (Pointing down due to the too low trunnion support piece)

Effectively you could only have the receiver contact two of the three support points. (Barrel Crown, Trunnion Support, and end receiver support)

Attached File


Cocking tube hanger pin support was also off when locked in the trunnion support.

Attached File


Plus just like the OPs jig the cocking tube rotation alignment jig was off. (too low)  Meaning you would weld the cocking tube in the wrong rotational orientation. (see red arrow in the pic below)

The cocking tube index rod was also too short for HK33 rifle builds due to the shorter cocking tube/handguard on the 33/93 guns, meaning the cocking tube alignment rod has to stretch farther over the barrel from the barrel crown/cocking tube alignment plate. (See first pic above)

Even with the barrel crown index pin shortened up as much as it could go (pushing the barrel crown/cocking tube index plate  as close to the tip of the barrel as possible) the cocking tube alignment rod being too short was barely supported in the jig to the point that it would slope downward due to its own weight and lack of support in the endplate.  

Attached File


I fixed some of the issues but I still need to resolve the trunnion support height issue.  Ultimately I just ran out of time and was hoping the seller would make good so eventually fixing it was put on the back burner for the time being.  I do have a couple 33K builds I need to finish so will probably pull it out of storage and finish dealing with the trunnion support height issue and then see if there are any other problems at that point.

Thanks for that JB,   I think mines off in about the same areas.  It was a solution that could have been a winner but if the guy making them has zero fucks to give I guess waiting for RTG to put some out again should be anyones plan looking for one.  

I bought this one because I was on the waiting list at RTG for something like 2 years and they never came back in stock.

Most of the issues can be fixed if you have a mill available.

However, the center trunnion holder being too low is a real challenge to solve.  My plan was  to try and heat it and when hot put it in a hydraulic press with two steel bars and try and squeeze it, hoping that squeezing it would lengthen it making it ever so slightly taller  If that didn't work I was just going to make a new one from scratch.

I fixed everything else and beltfeed said he would send me an updated trunnion support so I waiting for him to come through.  Then came a never ending list of delays and excuses as to why he couldn't ship a correct part.  My take is he was trying to string me along past the 90 day review window with his never ending list of excuses and "two more weeks".

I eventually boxed it all up after he never sent me the replacement part.  However, I do need to pull it back out and get the trunnion support fixed.  I will report back if its successful in heating/squeezing it longer/taller.

Got some welding done today.  Ran out of argon.  

You're doing an amazing job.

Sorry your argon is all gone. (I'll see my way out)

Nice!

I want one of those alignment jigs so bad. Been waiting on RTG to do them again. Even told them I could do a bunch of the machining if they sent me plans. Never heard anything.

@lancelot should have an update coming.  Assumed drill bit size in order #1 instead of measuring and sure enough it was wrong

Second bit in hand here in a box somewhere so will be moving forward.  Also secured 500 rounds of 40 ammo that I want to go run through it before blasting it and park on then spray finish.  


Also have the option to buy one of these in 357 sig..