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4/28/2004 12:10:46 AM EDT
Can an RPK-74 barrel be assembled to a standard AK-74 front trunnion? Noting the current lack of complete kits, the alternative seems to be using a bulgie kit with a kvar front end. Any thoughts or opinions out there?
4/28/2004 3:46:41 AM EDT
[#1]
worse case scenario is that the bbl. journal will have to be turned down to fit a standard ak-74 trunnion or that the trunnion hole will have to be opened up to fit the rpk-74 bbl. journal diameter.

k-var can advise you as to the journal diameter on the bbl. and the trunnion.
4/28/2004 9:05:55 AM EDT
[#2]

Quoted:
Can an RPK-74 barrel be assembled to a standard AK-74 front trunnion? Noting the current lack of complete kits, the alternative seems to be using a bulgie kit with a kvar front end. Any thoughts or opinions out there?



RPK-74 barrels are .908", Bulg/Russian AK-74 trunions are .867"

Romanian SAR2 5.45 guns are the old .907", as well as most .30 cal AKM  models from most countries...  Putting the RPK-74 barrel on a Bulg 74 trunion would obviously require turning the barrel down, a last resort when you have AKM stye trunions available.

-C
4/28/2004 1:33:26 PM EDT
[#3]
The dog ears on the front trunnion on a SAR-2 are 22.5mm apart. The RPK rear sight block is 24mm wide where it would go between the dog ears. How are builders handling that? Opening up the trunnion ears or reducing the rear sight block? I've seen pictures of the RPK barrels in the Romy 5.45 but not close up.  

Jor-el,
As far as my opinion. I think it would be easier to find Red Kryptonite than a RPK-74 front trunnion!

4/30/2004 9:35:48 PM EDT
[#4]

Quoted:
The dog ears on the front trunnion on a SAR-2 are 22.5mm apart. The RPK rear sight block is 24mm wide where it would go between the dog ears. How are builders handling that? Opening up the trunnion ears or reducing the rear sight block? I've seen pictures of the RPK barrels in the Romy 5.45 but not close up.  

Jor-el,
As far as my opinion. I think it would be easier to find Red Kryptonite than a RPK-74 front trunnion!




Yea that is something that I hadn't thought about, as I have a real RPK-74 front trunion, but I would definately open up the ears before making the rear sight block skinnier. The next best thing is t o  just use a Vepr IIK 5.45 and call it a day.
5/1/2004 4:32:17 AM EDT
[#5]
The next best thing is t o just use a Vepr IIK 5.45 and call it a day.

actually, that's the BEST way to go, imo.

repairing the receiver rear end can't be all that difficult.
5/1/2004 6:50:41 AM EDT
[#6]

Quoted:
Yea that is something that I hadn't thought about, as I have a real RPK-74 front trunion, but I would definately open up the ears before making the rear sight block skinnier. The next best thing is t o  just use a Vepr IIK 5.45 and call it a day.



chamberlin, you don't have to use a IIk do you? Any reason that a k would not work? Am I missing something?
TIA
5/1/2004 7:03:35 AM EDT
[#7]

Quoted:
The next best thing is t o just use a Vepr IIK 5.45 and call it a day.

actually, that's the BEST way to go, imo.

repairing the receiver rear end can't be all that difficult.



Tearing up a NIB Vepr is going to take more courage than I can muster.
Must consume massive quantites of favorite libation.
5/1/2004 10:09:35 AM EDT
[#8]

Quoted:
The next best thing is t o just use a Vepr IIK 5.45 and call it a day.

actually, that's the BEST way to go, imo.

repairing the receiver rear end can't be all that difficult.



YES FOR SURE!!! Definately the best, not NEXT best thinig!!!!
5/1/2004 10:35:36 AM EDT
[#9]

Quoted:

Quoted:
Yea that is something that I hadn't thought about, as I have a real RPK-74 front trunion, but I would definately open up the ears before making the rear sight block skinnier. The next best thing is t o  just use a Vepr IIK 5.45 and call it a day.



chamberlin, you don't have to use a IIk do you? Any reason that a k would not work? Am I missing something?
TIA



NO, the K model is not req'd, that's just what I am using... I bought two of them, and sold one to another friend making an RPK-74... I had that thing torn down so fast it wasn't even funny.. no remorse  Never even shot it. Hell man, have a drink AFTER you tear it down, not before!!! Celebrate!
I have the ass end all welded up and ready to go, as well as the starter bump rivet hole (don't need or want it). Just gotta put in fake spot weld marks per the original recveiver (the Vepr is TOO smooth) engrave selector markings and repark and paint. Anyone got some 'time' I could buy from them?

-C
5/2/2004 6:09:46 AM EDT
[#10]
This thread has provided GREAT info for me to complete my rifle!! Can a SAR2 be used to complete this build instead of using a VEPR IIK? Would the "dog ears" interfere with the sight block size of the barrel? I think that the barrel and trunion of a SAR2 could be interference fit since there is only a .001 size difference.

http://www.3cblueing.com/Tims%20Folder/Images/RPK-74%20Collage.jpg
5/4/2004 8:49:18 PM EDT
[#11]
I think all your questions are answered above...  
-C
5/5/2004 5:01:09 AM EDT
[#12]
yup. you can stuff the rpk-74 front end in an sar-2.

the alignment ears will have to be relieved to allow the rpk-74 rear sight block to locate.
5/6/2004 5:02:56 AM EDT
[#13]

Quoted:
yup. you can stuff the rpk-74 front end in an sar-2.

the alignment ears will have to be relieved to allow the rpk-74 rear sight block to locate.



RPK stuffed SAR-2 on the menu today.

Stuffed as far as it will go and won't headspace. No go goes, Go goes and round goes. I can't tell if the feed ramp is obstructing it from going further or the barrel is just seized. Any suggestions?

Lower handguard will have to be modified due to the thinner receiver of the SAR.

5/6/2004 8:38:28 AM EDT
[#14]
Hmmm. It would be wierd to have the feed ramp be blocking anything, being that a barrel used to be headspaced in this rifle.... the other variable however is Vartan's barrels....I have a take off barrel, so I know it will headspace and work.... these new barrels I have inspected and quized Vartan about, but I have not used one for a build... I am sure they are faced properly and all that, so I doubt it is an issue.. but I wonder....
At this point, it sounds like it might be seized up in there... I would pop that puppy out and emery cloth the journal for a smooth fit... lube it up on it's return into the trunion.... every AK barrel I have ever done it was possible to go past the point of perfect headspace, this combo should not be an exception. THere are these guys that have to have a .002-.004 press fit to be happy, I think that is insane...of course you don't want to be able to push it all the way in by hand, but a slight interference fit along with that fat barrel pin is going to be just fine.
Bummer about the handgarud too, how are you going to build it up? put a spacer in the receiver?  One more vote for the Vepr!
-C
5/6/2004 11:13:24 AM EDT
[#15]

Quoted:
Hmmm. It would be wierd to have the feed ramp be blocking anything, being that a barrel used to be headspaced in this rifle.... the other variable however is Vartan's barrels....I have a take off barrel, so I know it will headspace and work.... these new barrels I have inspected and quized Vartan about, but I have not used one for a build... I am sure they are faced properly and all that, so I doubt it is an issue.. but I wonder....
At this point, it sounds like it might be seized up in there... I would pop that puppy out and emery cloth the journal for a smooth fit... lube it up on it's return into the trunion.... every AK barrel I have ever done it was possible to go past the point of perfect headspace, this combo should not be an exception. THere are these guys that have to have a .002-.004 press fit to be happy, I think that is insane...of course you don't want to be able to push it all the way in by hand, but a slight interference fit along with that fat barrel pin is going to be just fine.
Bummer about the handgarud too, how are you going to build it up? put a spacer in the receiver?  One more vote for the Vepr!
-C



Chamberlin,
Thanks for the reply and advice. The sar-2 receiver that I am using for a host came from Century looking pretty poor. It had the brown paint glopped all over. The barrel didn't look all that hot either, so as to it being headspaced correctly I don't know.  The bottom of the chamber face of the barrel looks as though the rounds were stove piping or the guys at Century modified it. I never fired it or checked headspace on it. In retrospect I suppose I should have. I am going to give it one more try to press in the barrell a little more. I will change my pressing technique somewhat. The leafs on the rear sight block might be getting in the way. It is past the dog ears on the trunnion. If I'm not sucessful in pressing any further, I'm going to punch it out and follow your advice.
This RPK barrel is a single assembly. It was not part of a parts kit. I am using it on the sar as more of a learning experience. Tuition as Wecsog University can be expensive sometimes.
I have a complete parts set along with a Vepr to have a go at once I complete my remedial courses at WU.
Never fear, I won't screw up a plum RPK stock set . I'll mod the receiver somehow before I do that.
When you get your RPK finished, I would love to see some pics.
Thanks for your help.
5/6/2004 6:37:14 PM EDT
[#16]
No probs, Campy and I are always glad to help out... this is one of our favorite builds...
I will try to post some 'in progress' pics soon to liven up the thread...
The barrels KVAR has are relatively new manufacture, with newly made parts me thinks...
and no as you said, not from parts kits (i.e. demill rifles).  This can be a good thing or bad thing depending on your viewpoint....
-C

p.s. don't let that RoadRunner get you down! hopefully you can use your ACME RPK-74 to inihlate that little bird bitch! BeeBeep Zip -BANG!
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