Building a Yugo M72

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My life doesn't seem complete unless I have a pile of parts lying around that are supposed to turn into a gun at some point so I've started on my next one. This time I'm going to build a Yugo M72 RPK. I've ordered an 80% receiver from Childers (https://www.childersguns.com/AK-Receive ... lank-rails) which I'm still waiting on. But today I got the first, and probably most exciting delivery. A torched up M72 parts kit.
IMG_20190621_182048.jpg
Unlike an AR-15, as far as I can tell from reading the internets only the receiver is considered the full auto part for an AK, so that gets cut in half with a torch also at that point this isn't a firearm anymore. I'm not sure why the barrel gets cut as well, but is also cut into three heavy pieces. All the other pieces are there in their full Yugoslavian Cosmoline filled glory. And there is a LOT of cosmoline. The bag that had the trigger group was practically soaking in the stuff.

So far after a casual inspection everything seems in good shape. The sights look good and straight, as does the wood. The only part that might not be salvageable (or maybe it never is based on how they torch it) is the trigger guard which is a bit bent since it's holding the two halves of the receiver together.

Next step is going to be breaking out the mineral spirits and getting the cosmoline cleaned up, then on to the demilling.

Re: Building a Yugo M72

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Moar cosmo moar better.

The best way I have found to clean that stuff off is a hot garage in the summer. Put big parts in garbage bags, tie off the top with a zip tie to the end of the long part and hang that in the garage. Put a bucket under it and cut a small hole in the bottom of the bag. Leave it for...a while. Much of the cosmo should have leaked into the bucket.

An 8mm Mauser AK is on my 'oh please let me live longer' list.
In a bacon, egg and cheese sandwich the chicken and cow are involved while the pig is committed.

Re: Building a Yugo M72

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Sat down with a beer, about 20 pairs of nitrite gloves (I couldn't find my gloves that don't get eaten as fast) a bucket of mineral spirits, a brass brush, and some Rick and Morty. A few hours later and a few more dead brain cells and I got maybe 90% of the cosmoline off I think. Letting it try out and I'll check it out in the morning and take some more pics of the interesting bits.

Re: Building a Yugo M72

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I haven't been updating this thread but I have been working on this. If you google how to build an AK from scratch you'll inevitably see someone saying "don't expect this to be as easy as building an AR-15." That person is 100% correct. I haven't assembled anything yet and now I laugh at how hard I thought putting roll pins in to a lower was.

Before I can assemble anything I have to demill the RPK parts kit. That starts with the receiver, here are some close ups of the before state of the front of the torched receiver:

The left side:
left.jpg
The right side:
right.jpg
The round nubbins are, of course, rivets that have to be removed (in Soviet Russia there is no screwing). To do this you need to grind the rivet flat, then drill a bit into it so you have a pilot hole roughly in the middle of the rivet (preferably you want this to be drilled to a depth that will take you just into the receiver). Once you get the rivets drilled its time to grind the head rivet down till its flush with the receiver. The good news is that the receiver is already trash so you can just go to town. I didn't take many pictures of this process but here is the rear rivet ground flat:
flat rivet.jpg

Re: Building a Yugo M72

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Once you get the rivets drilled and ground you can just tear the receiver off the trunnion. There isn't any black art to this that I've found. I just slapped it in a vise and used pliers to twist the back sides of the receiver until the rivets popped. Here is the trashed receiver:
trash receiver.jpg
You'll notice its cosmoline city underneath the receiver:
cosmoine.jpg
You can also see all the remains of the rivets (they're shiny).

Now you need to take the barrel pin out to remove the barrel. I could have waited for this and just finished drilling out the rivets because the 3" barrel remnant on the trunnion is pretty worthless and if I damaged it with the drill bit I wouldn't have suffered but I had things in the vise already and I'd had a couple beers so I just took a couple good whacks with a punch and hammer and it popped out.
barrel pin removed.jpg
At this point I figured if everything kept going at this rate it was going to be a piece of cake. Sadly this is the easy part.

Re: Building a Yugo M72

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offensivename wrote: Thu Aug 01, 2019 8:38 pm There are easier ways to go about this for sure. Various parts kits come in different amounts of demilling. This kit seems about as much work as they come. A quick google found some that had these steps already done:

https://www.atlanticfirearms.com/produc ... t-romanian

But I wanted a yugo because it went with my M59 SKS and M57 Tokarev and thus I must suffer.
:roflmao:

poor baby
It is an unfortunate human failing that a full pocketbook often groans more loudly than an empty stomach.

- Franklin D. Roosevelt

Re: Building a Yugo M72

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Nice project! And yeah, the combloc parts kit builds are a whole different level than an AR Lego set. Put together a VZ58 from one a few years ago and I still love it.

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“Do the best you can until you know better. Then when you know better, do better.”
- Maya Angelou

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Re: Building a Yugo M72

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shinzen wrote: Fri Aug 02, 2019 9:17 am And at least you had the good sense to put together something that has readily accessible parts.

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that can actually be a problem. i spent an hour yesterday looking at 4 vendors deciding who to order what parts from. yeah, i know, first world problems, sucks to be me.
i'm retired. what's your excuse?

Re: Building a Yugo M72

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lurker wrote: Fri Aug 02, 2019 10:06 am would it make more sense to drive the rivets out once you grind the heads off? a hammer and punch might be easier than tearing it apart in a vise?
Maybe? I was following someone else's directions here (http://www.calguns.net/calgunforum/show ... p?t=325386). I think part of the issue is that, depending on where your AK comes from they can also be spot welded (pretty sure I read that somewhere). You can see his receiver popped off a lot easier than mine did.

Re: Building a Yugo M72

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offensivename wrote: Fri Aug 02, 2019 10:29 amYou can see his receiver popped off a lot easier than mine did.
Yeah, it can be on there tight. I had a decent amount of grinding to do on my trunion to get it off- basically had to cut the damned thing in half.
“Do the best you can until you know better. Then when you know better, do better.”
- Maya Angelou

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Re: Building a Yugo M72

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lurker wrote: Fri Aug 02, 2019 10:57 am whatever works, i guess. apart from a moisin i once owned, i know nothing about com-bloc guns. and which is correct, mosin (moe-sin) or moisin (moy-sin? mwaw-seen?)? curious minds want to know.
My Russian is very rusty but I'm pretty sure its Moe-sin the stress is on the O and in russian non-stressed vowels just kind of turn into a generic short e sound

Re: Building a Yugo M72

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offensivename wrote: Thu Aug 01, 2019 8:02 pm
barrel pin removed.jpg
The next thing I don't have a picture for, but in the image I quoted you can see the barrel stub stuck in the trunnion, that has to go. If you were concerned about the condition of the chamber you need to be careful here. I didn't have to be though. My technique for getting the trunnion out was to simply take a long 1/2 bolt place it on the rear of the chamber while the trunnion was in the vise and then whack the shit out of it with my 3# hammer.
trunnion no barrel.jpg
The amount of pounding this took was considerable and was a pretty good harbinger of how hard the other barrel components are to remove if you don't have a 12 ton press.

Re: Building a Yugo M72

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offensivename wrote: Fri Jun 21, 2019 11:30 pm Unlike an AR-15, as far as I can tell from reading the internets only the receiver is considered the full auto part for an AK, so that gets cut in half with a torch also at that point this isn't a firearm anymore. I'm not sure why the barrel gets cut as well.....
ATF changed the rules in 2005 I believe it was. IF the imported parts kit could be assembled into an otherwise banned firearm/non sporting firearm..... the barrel has to be "de milled too" and not just the receiver.

Re: Building a Yugo M72

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308Scout wrote: Fri Aug 02, 2019 11:05 pm
offensivename wrote: Fri Jun 21, 2019 11:30 pm Unlike an AR-15, as far as I can tell from reading the internets only the receiver is considered the full auto part for an AK, so that gets cut in half with a torch also at that point this isn't a firearm anymore. I'm not sure why the barrel gets cut as well.....
ATF changed the rules in 2005 I believe it was. IF the imported parts kit could be assembled into an otherwise banned firearm/non sporting firearm..... the barrel has to be "de milled too" and not just the receiver.
That 'makes sense.' It also brings up the next part which is getting the rear sight, the gas block and the front sight off of the barrel. These pieces are all press fit onto the barrel then pinned. The first issue was removing the pins. I tried my roll pin punches and they just aren't the correct thing for this so I ordered up a set of flat punches and kept spraying the pins with some penetrating oil. The small pins in the front sight and the gas block came out easy enough. The rear sight's one big pin . . . not so much. I did a lot of pounding and a lot of scuffing up the blueing of the sight but no movement. Eventually I came up with the bright idea of putting the sight into the vise with a small remnant of one of my many broken punches that was centered on the pin. Tighten the vise and eventually the pin moved enough that I could punch it out with my trusty 3# hammer and a bigger punch! The sweet smell of penetrating oil and victory!


Until I tried to get those pieces off the barrel stubs that is.

Re: Building a Yugo M72

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With the pins out you have to remove the various components that are pressed onto the barrel stubs. Without a press this can be challenging. For the rear sight block and the gas block I used a piece 1" soft metal pipe. The pipe fits over the barrel and sits on block. This lets you pound the living shit out of the barrel, pushing the block off. The gas block came off easy enough once I had a long enough piece of pipe to use. The rear sight block took a bit more effort to pound off, but eventually I got it off.
rear sight.jpg
gas block.jpg
The brute force approach is definitely not kind to the blueing on the gun, but you can see on the barrel stub that the who thing was blued while assembled.

Re: Building a Yugo M72

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With the gas block and rear sight off of their barrel stubs there is only one piece left, the front sight and the bipod.
front sight.jpg
The threaded barrel had a thread protector screwed on, which was easy enough to take out, just make sure to put the spring loaded anti-rotation pin in a safe place once you unscrew the thread protector. The bipod isn't attached to anything, its just retained between the front sight and a step on the barrel. Finding a way to get this damn thing off took almost a month of cursing and banging. Unlike the other pieces there's not a great place to put anything to help pound the front sight off. I tried using the bipod to push on the front sight post, but it didn't seem to work, especially because its much thinner than the rest of the pieces and I was worried about bending it.
front sight back.jpg
I finally came up with a solution though. I bought a 1/2" brass punch and used that to pound on the flat at the base of the rear of the front sight, putting the end of the barrel onto the flat part of my vise then beating it with the trusty 3# hammer. I'd spray some CLP into the front, hit a few times, flip it over and do it from the back, then repeat that several times a day. Finally today I noticed that I could see the barrel start to budge a bit, so I went to town and beat the crap out of the front sight and was finally rewarded with a separate front sight, bipod, and trash barrel stub.
front sight broken down.jpg

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