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I received my K-VAR RPK-74 barrel assembly last week and just received the 23mm AK-74 (new) trunion Saturday. I measured the barrel and it seems to measure + .9075 and the trunion is + .886. Does this sound right? This trunion doesn't have the top rivet holes drilled yet, so I may drill the receiver and trunion at the same time.
Also, I can't seem to get the AK-74 gas tube to fit. Does the gas fitting need bumped forward a bit?
 

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Discussion Starter · #44 ·
gtbehary said:
I received my K-VAR RPK-74 barrel assembly last week and just received the 23mm AK-74 (new) trunion Saturday. I measured the barrel and it seems to measure + .9075 and the trunion is + .886. Does this sound right? This trunion doesn't have the top rivet holes drilled yet, so I may drill the receiver and trunion at the same time.
Also, I can't seem to get the AK-74 gas tube to fit. Does the gas fitting need bumped forward a bit?
G,
My gas tube does not fit as well. I have been meaning to call k-var and ask them if these fittings are where they are supposed to be. Usually all they tell me is send it to a qualified smith. (that's no fun) I get compressed air through the gas port but I'm not sure that it's on properly. I did not start with a new trunnion so I don't think mine was the same.
Have you received your stockset from IO yet?
 

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Dirtalert said:
G,
My gas tube does not fit as well. I have been meaning to call k-var and ask them if these fittings are where they are supposed to be.
You may have to shave a bit off of the front of the gas tube. Just use a file and go slowly. Is the gas block already pinned? If not, you may be able to push the GB forward that ever-so-small amount to allow the tube to clear, and THEN drill out the pin holes.

Dirtalert said:
I get compressed air through the gas port but I'm not sure that it's on properly.
You should be able to use a paperclip to "feel out" the hole. Kinda hard to mess this up, however... the hole in the GB is much larger than the hole in the barrel so you have plenty of room to screw up.
 

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Discussion Starter · #47 ·
hcpookie said:
You may have to shave a bit off of the front of the gas tube. Just use a file and go slowly. Is the gas block already pinned? If not, you may be able to push the GB forward that ever-so-small amount to allow the tube to clear, and THEN drill out the pin holes.


You should be able to use a paperclip to "feel out" the hole. Kinda hard to mess this up, however... the hole in the GB is much larger than the hole in the barrel so you have plenty of room to screw up.
Nothing is pinned in yet, just pilot holes. But everything is on very tight. I don't know if they can be moved without major reconstruction with the "southern hand sledge" (That was for Winn :smile: ) I planned on pinning the barrel first and dealing with the other as I came to it.

I had no time to work on it this weekend between lawn care and my work computer's hard drive dying. (no backup to speak of. I live life on the edge. :smile: )

Regards
 

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Discussion Starter · #48 ·
"Hope you fare better than me G. I drilled and pinned the barrel this afternoon and now headspace is off. This is not funny anymore."

This was posted on gtbehary's thread. My question is anyone think a new bolt would help me with headspace. Is the Bulgarian bolt the same as Romanian in the AK-74 / Sar-2? Opinions please. :)
TIA
 

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Dirt-- I've swapped bolts on RPK '47 back and forth to get one to head space and it didn't care where the bolts came from.

I would guess the 74's should be the same.

 

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Discussion Starter · #50 ·
Winn R said:
Dirt-- I've swapped bolts on RPK '47 back and forth to get one to head space and it didn't care where the bolts came from.

I would guess the 74's should be the same.

Winn, I pulled out a Bulgarian Bolt of a kit I had put away. It is a more substantial part than the Romy Bolt. It would not close and lock up in the trunnion at all. Lugs are all bigger. I guess I'll order a Romy bolt just for grins and see if it will headspace. Being that it is new maybe it will fit better. Or am I just throwing good money after bad?
Thanks for the advice
 

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Chinese curse-- May you live in interesting times

Why thank me for something that was wrong? But I learned the Rommie and Bulgy lockups are different-- I thank you for that.

Damn, I know how you dreaded this possibility from the get go--

All my '74's are Bulgy. Gots lots of parts though. Want me to open a bulgy trunnion to the dimension of your barrel? Be happy to give it a try. And got a machinist coming by on Sun who could probably tell me how.

Tell me again why the barrel can't be moved and repinned?
 

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Discussion Starter · #52 ·
Winn,
I thanked you because you provided the inspiration and motivation for me to get off my lazy ass and drag out a put away Bulgy 74 kit. :smile: You know it takes some effort to go to my secret underground bunker (closet) to retrieve this stuff.

A brake cylinder hone worked really well for opening up this Romy trunnion. A little too well I suppose. I thought the trunnion / barrel combo was too loose. I guess I confirmed it when the simple acts of handling and drilling for the barrel pin caused me to lose headspace. It was right on before I drilled and pinned.

I guess I could move and try to repin(oversize?) but I need to replace the trunnion. If all else fails this barrel / bipod will make a great walking cane. Most likely get some funny looks at the Mall.
 

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Dirt-- a buddy came over today who is a machinist and he explained how to bore out the trunnion. It's doable.

 

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Discussion Starter · #54 ·
Winn R said:
Dirt-- a buddy came over today who is a machinist and he explained how to bore out the trunnion. It's doable.

Why didn't you go ahead and post his explanation?

Was it too boring? :sorry: I couldn't resist.


Are you referring to boring out a 22mm Bulgy or boring out a 23mm Romy trunnion? I have to order stuff.
Does this solution require a Mill or lathe?
Since I misdrilled for the barrel pin, I'm not sure what I'm going to do now. I need to get a new bolt to see if it headspaces. I'm not sure if the century people modified the one out of the SAR-2.
 

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Dirtalert said:
Was it too boring? :sorry:

Are you referring to boring out a 22mm Bulgy or boring out a 23mm Romy trunnion? Does this solution require a Mill or lathe?
.
Sorry Dirt --I lost this thread.

This is like a poker game. It ever gets boring, just raise the stakes.

And it involves the use of a 23 mm boring head that is connected to a smooth 22 mm center shaft. This would allow the use of the Bulgarian trunnion and bolt on the Romanian barrel. it's doable with the drill press because the center shaft gives stability.
Having put a number of these together using welding in one form or another, I'm quite comfortable with that and unconcerned reference the heat issues.

Maybe the easiest thing would be to pull it apart, weld up the holes in the trunnion and barrel, and redrill at the right headspace.

 

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Discussion Starter · #56 · (Edited)
Winn R said:
Sorry Dirt --I lost this thread.

This is like a poker game. It ever gets boring, just raise the stakes.

And it involves the use of a 23 mm boring head that is connected to a smooth 22 mm center shaft. This would allow the use of the Bulgarian trunnion and bolt on the Romanian barrel. it's doable with the drill press because the center shaft gives stability.
Having put a number of these together using welding in one form or another, I'm quite comfortable with that and unconcerned reference the heat issues.

Maybe the easiest thing would be to pull it apart, weld up the holes in the trunnion and barrel, and redrill at the right headspace.

No problem Winn, I think this thread was lost from the start.
I decided to raise the stakes. I threw another SAR-2 at this project. I tore it down this morning. I did not bore out the trunnion at all. The barrel was already dressed down from the emery paper strip. Instead of reducing the ears on the trunnion, I took some material off the front sight base. I pressed the barrel in the new sar. It goes in smooth and easy to a point. Then it acts exactly like the other one. It's jamming up on something just like the first one did. It still needs to go in further for headspace just like the other one did before I honed out the trunnion. I still can't figure out exactly what this is hanging on. I haven't had a chance to look at it anymore this afternoon / evening. Maybe the barrel tapers up and I need to dress it down further up on the barrel. We'll see.
The original SAR-2 will become a donor for a AK-74 kit. I'll take this trunnion out and use a bulgy kit.
 

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Every time I've pieced together barrels and trunnions from different sources it's been a pain.

Not having actually measured, it's only a supposition that there is a lot of area within that portion of the trunnion where the barrel pin can be located and that the wide latitude in placement means that most barrels and trunnions from different sources will have hole locations which vary widely.

It's a real shame that K VAR's rpk barrel did not come with the trunnion.:confused:

 

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Discussion Starter · #58 ·
Winn R said:


It's a real shame that K VAR's rpk barrel did not come with the trunnion.:confused:

Yes, and I could not get an answer from Bob as to why it was not included.
He just said, "Vere are you gonink to get an RPK receiver". With all the talent that you guys on this board are exhibiting, I think that would be the least of my problems. It would be easier to find a receiver. I haven't seen anyone machine a homemade trunnion yet but I'm sure someone on this board will.

I noticed when I pressed out my bbl on the original SAR-2. The area above where the barrel pin goes is cracked. It is cracked all the way across from ear to ear. I left myself wide open on that last sentence. :smile:

Where it is pressed in the new SAR-2, I noticed that the rear sight base needs to come forward for the dust cover to fit. At the same time the RSB needs to come back for the gas tube to fit. All the components on the barrel need to be drilled and pinned. I need to find out if they are supposed to be pressed on at the right spot..

It is getting about time to tear up a Vepr.
 

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Before you pull the barrel out, give it a spray of tool blue or maybe a mist of white paint. When the barrel comes out, the paint line should give you an indication of what it's hanging up on.

The feed ramp could be at just enough of an angle to start jamming the barrel tight after a certain point.

After all these posts, I have grown interested in what's causing the problem. I hope you find it soon.
 

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Discussion Starter · #60 ·
Rhino_66 said:
Before you pull the barrel out, give it a spray of tool blue or maybe a mist of white paint. When the barrel comes out, the paint line should give you an indication of what it's hanging up on.

The feed ramp could be at just enough of an angle to start jamming the barrel tight after a certain point.

After all these posts, I have grown interested in what's causing the problem. I hope you find it soon.
Thanks Rhino.
At least this time I think it is the bullet guide holding it up. The barrel is absolutely flush against it. Which is what I was calling the feed ramp in previous posts. Is it the same thing?

What are my options at this point?
1. Press barrel out some and take some material off the bullet guide?
2. Find a bolt with more meat on it, if it exists?
3. Quit while you still have a couple of rifles that are intact?

Option 1: Probably won't feed right after that.
Option 2: Long shot
Option 3: In a move hailed by the anti-gun lobby, Georgia man tears up 10 rifles in exchange for one un-fireable RPK. :woot:
 
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