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Posted: 2/5/2010 2:20:46 PM EDT
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building my second AK (havent shot the first, but went fairly smooth) and things were goin pretty good, then all of a sudden when headspacing my rifle I caught a bit of a snag..... I think I may have headspace issues to begin with requiring a bigger pin, but the bolt issue binding bothers me more. when I pushed the barrel out a bit searching for where it would headspace, I discovered the bolt binds when it starts to turn to close. If I force it, it will close, but to open it I have to smack it with a block of wood or something to open it. I'll try and post pictures in a bit, but I believe it's hanging up on the left side of the rifle somewhere. anyone else have this problem? No blatent burrs or dirt, it just seems it should work. what should be my next step? these parts are NON-MATCHING, and came from the cheapo parts kits at Aim. I thought about attempting to file away/polish parts of the trunnion but didnt want to do that without asking the AK pros. Any help appreciated!
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http://i112.photobucket.com/albums/n166/psode27/DSC01812.jpg
http://i112.photobucket.com/albums/n166/psode27/DSC01811.jpg http://i112.photobucket.com/albums/n166/psode27/DSC01815.jpg http://i112.photobucket.com/albums/n166/psode27/DSC01816.jpg FWIW, these are built on NDS receivers, and no binding exists between receiver rails and trunnion. The bolt will currently CLOSE on my NO-GO gauge, so the binding is not affected by too tight of headspace. Any help appreciated! |
Well it's about time. These kinds of issues are to be expected when building with a non-matching parts kit and especially with the numerous barrelless kits. Speaking from experience it is good to ask before starting to file things. But in this case filing/fitting is precisely what you need to do. If you look on the back for most bolts there is a slightly irregular area where they have been ground down/filed for this very reason (to get them to fit together). My biggest fear is that there are some out there building without checking and are getting excessive headspace and don't realize it. Go slow and make sure you are addressing (filing) the right place. As for the larger barrel pin idea, that has always concerned me and restoreit gives some nice images of why this should probably be avoided. The space between the chamber and the pin to begin with are rather small, then to reduce that space by drilling for a larger pin just scares me (while others are quite comfortable with it). So disregard my paranoia about the oversized barrel pin if you want, but I can say having done mismatched kits you do have to file/polish things occasionally. Good luck and be safe. 
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Thanks for your input! I won't be doing a mismatched kit again. As I was sweating and getting dirty (ha) removing scrap receiver and rivets on another kit this already disassembled kit looked too good to be true.... That was before a lot more reading. I guess i'll try and narrow down the binding area and attempt to file/polish. As far as the "bigger pin" fix, I havent really looked that far into it, i just know some people do it. Is there any alternative to make this kit work? I have seen a pic of a dissected barrel, have people had dangerous issues before? should i just drill all my rivets out and move on to bigger and better things? buy a different bolt and try that?
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| alright, after some slow and tedious filing, the bolt operates pretty smoothly both by hand, and in the carrier. I re-set the barrel in the trunnion, and headspaced the rifle again. the go gauge would close about half way down, and the no-go gauge would just barely turn off of 12 o'clock. Any other fixes for headspace problems other than the larger pin? I'm pretty close to passing, in that case would a bigger pin be okay? is there anyone I could send my POS to and have him make it right? Thanks! |
| I have the same issue on an all matching serial number Romanian G kit. When I received the kit the back of the bolt lugs had already been filed on (another story). The bolt will rotate and lock but if I put a Go gauge or cartridge in the chamber it does not rotate close. Further examination shows that the barrel is pushed all the way down to the barrel face stop. My other Rommy has around .005" between the end of the barrel and the stop. I am looking at having to put in an oversized pin as the lugs have already been filed .007" and all of the "pad" area has been removed from lugs. I guess the QC wasn't very good at the factory or it never passed QC because there is no way it could have ever been fired. |
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Quoted:
No reputable builder files or grinds the bolt lugs to adjust the headspace on an AK.  The proper method is to move the barrel and install an oversize pin.That's right, but we're not just talking about headspacing. A quick check with your eye (or calipers if you must) will show you that is where they adjust the bolt to get it to function properly. As for headspacing, that is 100% barrel location (assuming your barrel is not shot out like so many Yugo barrels) as long as the bolt is where it should be.
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| Is there anyone on here that will headspace/install bigger pin for me? local gunsmith doesn't know much about AK's, and doesnt own a mill or anything that would be up to the task. As far as the bolt function and binding, it hangs up just a little bit now, but I think with normal shooting it may smooth out. I am new at this and not wanting to jack anything up! I appreciate your replys! |
| I too will need to adjust the headspace by reseating the barrel. Looking at AK-Builder there are (2) different oversized pins with a diameter .302" and .315". Does anyone know what size of drill bit to use and the appropriate reamer to use? I have tried to call AK-Builder but the phone is always busy. Thanks. |
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