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Old 04-11-2011, 10:42 PM   #1
kurbelgehause
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Default AK47 Barrel/Trunnion Fit

Hello all,

I am working on assembling a kit with a European AKM trunnion from one rifle and an AK47 barrel from another with the threads lathed off. Anyone know what the barrel journal o.d. and trunnion i.d. should be for a proper press fit?

Thanks!
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Old 04-11-2011, 10:53 PM   #2
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.908 on the barrel...23mm trunnion with .003-.004 press fit.
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Old 04-11-2011, 10:55 PM   #3
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All the sizes are here>
http://pookieweb.dyndns.org:61129/ak...dimensions.htm

But the relevant size is the actual trunnion ID you are using. Turn down the barrel to within .0015" to .002" for an interference fit. Trunnion ID's vary from the 23 mm nominal size.
If the AK47 barrel is populated with AK47 components you will have to modify the RSB or the trunnion "ears" to fit the barrel. Just an FYI.

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Old 04-11-2011, 11:01 PM   #4
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...actually all of the registers are different between
the AK-47 and the AKM barrel components.

here's our sticky, which probably came from pookies work ...

http://www.akfiles.com/forums/showth...876#post305876
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Old 04-11-2011, 11:34 PM   #5
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Quote:
Originally Posted by bluak47
...actually all of the registers are different between
the AK-47 and the AKM barrel components.

here's our sticky, which probably came from pookies work ...

http://www.akfiles.com/forums/showth...876#post305876
If you would read the first post you'll see it did not come from Pookies work.......


Quote:
Originally Posted by a-kmanator
.908 on the barrel...23mm trunnion with .003-.004 press fit.
This is entirely too much interference fit IMHO. .001-.0015 is all that is needed.
With .003-.004 , you'd have a hell of a time headspacing it.
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Last edited by loner42; 04-11-2011 at 11:40 PM.
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Old 04-12-2011, 02:52 PM   #6
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The standard for press fit is 0.001" interference for diameters less than one inch. AK trunnion can have a bit more "give" than some female press fit items but not much more. The trunnion can crack if the barrel is too large. The diameter is near to to one inch and 0.0015" is usually alright but 0.002" may or may not be a bit too much. It doesn't have to be that tight.

The other issue is fitting the wider milled receiver rear sight base to the trunnion. It can have material removed from the bottom of it so that it passes over the trunnion. It is possible to widen the trunnion slot but this leaves very little of the trunnon's "ears."
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Old 04-13-2011, 06:40 AM   #7
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All,

The barrel is stripped with no original components on it. I have some AKM components to press on. Any hurdles there besides mismatched cross pin holes? Thanks for the replies. Great information!
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Old 04-13-2011, 08:49 AM   #8
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It would be helpful to know what country of origin your parts are from. If you are using an AK47 barrel then AKM parts will not fit as the journals are smaller.

Here again the above reference list will for the most part tell you what fits what.
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