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Posted: 10/3/2005 6:35:50 AM EDT
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Headspace – everyone seems to says check it – but not what to do about it – well ok. Check done – head space too much (about .010 too much). Now what? Try different bolt? - barrel trunion? - take to the gun doctor? - – Hmmmm this could get expensive – might be cheaper to just buy another kit and start over. I guess it would help to have a pile of parts laying around. Any suggestions? Lesson learned – never buy a kit unless you KNOW it has matching numbers. |
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i have a simlar problem with a MAK-90, so it isn't just kits. What i was told was that i would need to punch out the barrel pin, get the barrel to where it needs to be to properly HS, drill an oversized hole for an oversized barrel pin. Makes sense to me, that's why that MAK is sitting waaay in the back of my safe. |
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The standard barrel pin is 7mm (0.276) so if you can find anything a little bigger you would be fine. There are places that sell 7.5mm barrel pins but I will have to search as well... Just get the pin out and measure to confirm the size you have. I have read that some of the Rommy kits may have 7.5mm pins already... I have not had to do this yet myself... |
I take it your saying it failed the "No-Go" gauge. Meaning that your bolt closed with that gauge. Have you tried the "Field" gauge? Just because a kit has matching numbers doesn't mean it will headspace correctly. Can you send the kit back? |
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Yo - Hammer in PA >>Have you tried the "Field" gauge? << Not having a field gauge I put a .008 shim under a no go and it still goes. I put a .010 shim under the no-go ganges and it won't >>Just because a kit has matching numbers doesn't mean it will headspace correctly<< I'm sure that is true but I would say the odds are MUCH greater on a kit that has matching numbers of being OK. This is my first kit out of 5 that doesn't have matching numbers and It's the one with headspace issues. >>Can you send the kit back<< Well I'm sure I could try - but the kit only cost me $80.00 and looks super (like new), other than this - and I'd like to try and fix it - But If I can't I'll have my first pile of parts. |
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bottom of the page....http://globaltrades.com/ak_receivers.html "Assembly Pins & Oversize Pins You only need the standard pins for normal assembly of AKs, but if you run into problems, the oversize pins can save you a lot of grief. They are about .001" bigger than the standard pins. We bought these to solve problems in our rifle assembly business, but we decided that we should make them available to our customers." |
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MSC Direct<--- you can order pins here, just cut to length. 7mm drill rod<--- For those needing to replace those pesky barrel pins ... and HERE is the stuff that GT sells (I think).. It is sized at 0.0014 over the 7mm barrel pin. It is the same as a "J" sized drill bit. Keep in mind that these are a couple of bucks for 36" of pin. Just cut to fit. |
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Yo aztroop and Mack_Bolan If the barrel is moved toward the receiver .010 to clean up a headspace issue -- if my caluclations are correct - to keep everything "round" the minimum oversized pin should be .020 over stock size. MSC Direct looks like a cool site!! Yo TerryG3 >>Actually, I wouldn't be concerned over only 10 thou.<< I have shot the gun and spent cases show no signs of a headspace issue (flattened primers - cracked/split cases - streached cases). .010 might be able to be considered a borderline problem. |
| I had a case where both gauges fit in a matching numbers AMD-65 after assembly. I pressed the barrel pin back out, and pressed the barrel in a little farther until the no go gauge didn't go and pressed the barrel pin back in. There is a range, despite what logic would tell you, where the headspace is adjustable by barrel depth in the trunnion without redrilling the pin for an oversized one. That is what I would try first. |
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Yo old_school_1960 and 2FALable >>There is a range, despite what logic would tell you, where the headspace is adjustable by barrel depth in the trunnion without redrilling the pin for an oversized one.<< Interesting - might be worth a try. ALSO I wonder which way the barrel tends to drift - In (toward receiver) form recoil or out from breach pressure???? I assume the pin keeps it from going one way or the other. If "in" maybe one could just relieve that side of the cut in barrel slightly if after doing what you suggest and the pin pushes the barrel back out. This might be worth a try for SMALL adjustments. |
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Well because I'm a dangerous freak I know what I would do.. but it's just me. Being off the amount you are, I'd go fire the beast and few times and then recheck the headspace. It's either going to get worse or get better... But I certainly wouldn't advocate anyone else do something just because I would. |
I have done lots of stupid things, but That takes the cake!... Thanks!...I feel much better about myself now!.. 
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all i can say was my factory built MAK90 has excessive HS and routinely tears the ass end off of the fired case leaving the rest in the chamber.. I won't shoot that gun anymore until i have corrected the problem. |
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