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Gunco Samurai
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Discussion Starter · #1 ·
Would anyone know if a Romanian 23mm Trunnion would work for a Bulgie RPK74 assembly? :thankyou:
 

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Gunco Samurai
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Discussion Starter · #4 ·
OOps, I should have been more specific, KVAR has a 23mm RPK Trunnion, I'm wondering if that would work, its romanian. If it won't and I still want to so the project I'll probably go with a milled reciever. That would be closest to the clone I'm thinking about anyway. Bulgie RPK74F much like the one on this page HERE . What do you think?
 

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Since I didn't wan't to mess around with the bulged receiver, I opted to buy a new 5.45 x 39 trunion from K-Var. It is a 23mm new trunion with no upper rivet holes drilled. The K-Var site has it listed as "AK-184 TRUNNION BLOCK AK-74 ~ (5.45X39.5)23mm".
That was the easy part. When tried the the bolt to see if it matched up, there was no room for the bolt to start rotating. The ramp that facilitates rotation of the bolt was so long that it just stopped the bolt. I had to grind away at the ramp until the bolt rotated up and locked into the lugs. This ramp is not that handy to get to with a dremel tool, so needless to say, my RPK has the ugliest ramp around. It does work now though.
This was the hardest barrel that I ever pressed in place. I actually ruined a Xebec press block, along with scoring the my new K-Var RPK 74 barrel assembly.
Once pressed, the barrel headspaced easily. I then drilled the barrel pin and re-checked the headspace.
When using a standard AK-74 23mm trunion (as I did) instead of using a real RPK trunion, (as I should have), you also come across the sight base width problem.....it don't fit between the trunion ears....more aggrevation and more fitting.
I believe the quickest and easiest method of building somewhat of an RPK-74 clone would be to get an RPK-74 trunion and mill off the bulges and use a standard Global receiver (heavy wall to make up for the narrower RPK trunion).
 

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Gunco Samurai
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Discussion Starter · #6 ·
If I built on a Coldsteel RPK blank I could keep the bulges and have a more authentic rifle. The key part for me is that I don't see any RPK74 trunnions anywhere, KVAR only has the Romanian 23mm 7.62 RPK trunnions. Could that work? Still I think about the milled reciever route more and more. Firing Line has a 74 underfolder reciever that would do the project nicely and keep it as close to a RPK74F as I could get. The only problem is that they'd have to turn down the barrel to get the fit.
 

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Polish Taipan said:
If I built on a Coldsteel RPK blank I could keep the bulges and have a more authentic rifle. The key part for me is that I don't see any RPK74 trunnions anywhere, KVAR only has the Romanian 23mm 7.62 RPK trunnions. Could that work? Still I think about the milled reciever route more and more. Firing Line has a 74 underfolder reciever that would do the project nicely and keep it as close to a RPK74F as I could get. The only problem is that they'd have to turn down the barrel to get the fit.
I haven't been able to find a true RPK 74 trunnion anywhere. Short of using one out of a Vepr, I don't think you will find one. I don't think the 74 bolt is going to work with a standard AK47 trunnion.

The milled underfolder RPK-74 would be cool. I vote turning the barrel down. You will still have the rear sight block/trunnion ear fit issue but that can be resolved. I would think you would also have a fit issue with the lower handguard and milled receiver.

Please keep us posted on your progress.
 

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If I had to do it over again, which I won't, I would turn the barrel down to 22mm and use a standard AK-74 trunion. The site base would still need to be modified.
 

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Gunco Samurai
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Discussion Starter · #10 ·
I haven't even bought the barrel yet, just planning. I'm thinking the Bulgarian RPK74F is the way I want to go. I'd have to have Firing Line built it instead of myself as I don't know how to have the barrel turned down to 22mm and am not sure about the fitting of the rear sight base. What do you guys think?
 

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Since the barrel and the milled receiver are both high dollar components, if I were you I would have firingline build it. If you decide to build it yourself the problems you are concerned with can be addressed. Take the barrel to a machine shop and have them turn it down or use a cloth backed sanding belt to reduce the barrel down. Read my thread. Winn suggested this. Put the barrel in a vice and use a shoe shine method with the sanding belt. You would be surprised how much this will take off. Be careful and check the dimensions often.

The rear sight leaves, or whatever you call them, that fit into the dog ears of the front trunnion can actually be bent in using a c-clamp. That way you would not have to reduce the ears on the trunnion or file down the rear sight block. I thought the bolt carrier would drag on this but it runs into the gas tube with enough clearance. You can always remove a little from the bolt carrier body if it hits. Mine didn't.

You will still have to pin all the components on the barrel as the kvar barrel assembly has nothing pinned on it. You still will have to drill for the barrel pin. You will still have to adapt a lower handguard from a stamped receiver to a milled receiver. There is not much area on a milled receiver for the handguard to fit into.

I had only built on two demilled rifle kits before this project came up. It's a whole different ballgame. Here's an idea. You can get one of those 74 barrel and trunnion assemblies from kvar for cheap.http://www.k-var.com/product.asp?0=205&1=206&3=450

You can use the trunnion to see if you can reduce the barrel and address the sight block issue. That way you are not using a 400.00 receiver to try out something that you are not sure about.

I think you can build it yourself but if you don't want the headaches let them do it.
 

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I just purchased two RPK bipods from Kvar. Starting with an AMD-63 kit, I am going to make a very short stub forearm to finish off the front of the receiver, attach the bipod (using a specially adapted muzzle brake) and attach the front grip off the side to clear the bipod.
 

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Gunco Samurai
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Discussion Starter · #13 · (Edited)
Hey Dirt, I actually just happen to have one of those short 74 barrel assemblies :thumbup1: . I'll read up on the posts. I'm assuming the Firing Line reciever is drilled for the barrel pin (can't really picture it in my head), would I then press the barrel in, headspace, then drill the barrel pin hole with the barrel in? I'll actually have a Xebit press jig soon that has a milled jig on it, so I'll have that tool to do it. What a build it could be!! I guess I'll be working some more extra shifts at the hospital to put this one together.

Gary, You kind of lost me on that last reply.
 

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Gunco Samurai
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Discussion Starter · #14 ·
Lets see if this pic will post so everyone can see what I'm thinking about. The pic is of a 5.56 RPK-F but Arsenal make the same one in 5.45.
 

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Polish, the firing line receiver is not drilled all the way through but it has a starter hole. The procedure that you describe is the way I did it on the RPK build. The new front trunnions have only the starter hole. I used a drill press and drilled slightly undersized and finished off with a reamer. hcpookie was kind enough to supply me with links to get the reamer from Travers. It's on page 4 of the thread.

Maybe someone can chime in on the best way to modify a stamped lower RPK handguard to fit the firingline milled receiver. There is not much area for the handguard to fit into. Or maybe you can find the furniture already made for it. You would figure kvar would have some since Arsenal builds the RPK on milled receiver.

It will be a sweet build. Personally, I would see if firingline would leave the eagle logo off. Don't get me wrong the eagle is cool but I think I would get them to put the Playboy Bunny on it. :wink:
 

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Gary said:
I was just mentioning that I was going to build an RPK/AMD hybrid. I have to trim the lower handguard way back to clear the bi-pod. I also am swinging the front grip 90 degrees to the side since the bi-pod completely covers the barrel on the bottom.
george
 

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Gunco Samurai
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Discussion Starter · #17 ·
As far as the handguards go, I'm wondering if Soupbowl could make a pair? Gonna give em a call here in a little bit.
Maybe instead of the eagle being etched into the reciever they'd put a taipan on there for me :) .
 

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Gunco Samurai
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Discussion Starter · #18 ·
gtbehary said:
Gary said:
I was just mentioning that I was going to build an RPK/AMD hybrid. I have to trim the lower handguard way back to clear the bi-pod. I also am swinging the front grip 90 degrees to the side since the bi-pod completely covers the barrel on the bottom.
george
Ooops, I could have sworn your name was Gary, lol, sorry. Your hybrid sounds cool, love to see it when its built.
 

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gtbehary said:
Gary said:
I was just mentioning that I was going to build an RPK/AMD hybrid. I have to trim the lower handguard way back to clear the bi-pod. I also am swinging the front grip 90 degrees to the side since the bi-pod completely covers the barrel on the bottom.
george
George, are you going to use the stock that came with the 63 or are you going to clubfoot it?
 

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Gunco Samurai
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Discussion Starter · #20 ·
Dirtalert said:
George, are you going to use the stock that came with the 63 or are you going to clubfoot it?
Please say you're going to clubfoot it :) .
 
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