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Re: FTE / Hard extraction with AKM

Posted: Mon Nov 03, 2014 8:27 am
by Blackstuff
Use brass or by a vz58 MARS :grin:

Seriously though my Steyr AUG used to hate lacquered stuff (i think it was Barnaul). At one point i had to put the charging handle against the front wall of a foxhole firing point and use my entire body weight to clear the case :bad:

Re: FTE / Hard extraction with AKM

Posted: Mon Nov 03, 2014 9:56 am
by snayperskaya
Here's a couple of pics of my bolt and carrier for comparison, they don't look any different to yours

Image
Image

I have got mine apart at the moment and noticed that the bolt carrier will move back about half an inch before the bolt itself begins to move rearwards, the first half inch or so of carrier movement is actually turning the bolt out of battery so if a case is stuck that first half inch of carrier movement is turning the bolt around the rim of the case and it then jams the carrier once the bolts out of battery because the whole assembly cannot then move rearward if that makes sense.Mechanically wise there is very little to go wrong so I'm going with the sticky laquer theory.I'd strip all the handguards off it and stick a couple of kettles worth of boiling water through the chamber and barrel to make sure everything is flushed out and whilst it is still hot give it a good scrub followed by a lubing.Have a search on the ak47 subforum on ar15.com for some threads on flushing barrels etc.

Before giving up on milsurp see if you can find the stuff with copper-washed cases rather than laquered.The 54r Russian milsurp I use in my Dragunovs is copper-washed and I've never had a single hard extraction in either of them.

Re: FTE / Hard extraction with AKM

Posted: Mon Nov 03, 2014 10:46 am
by SevenSixTwo
snayperskaya wrote:I have got mine apart at the moment and noticed that the bolt carrier will move back about half an inch before the bolt itself begins to move rearwards, the first half inch or so of carrier movement is actually turning the bolt out of battery so if a case is stuck that first half inch of carrier movement is turning the bolt around the rim of the case and it then jams the carrier once the bolts out of battery because the whole assembly cannot then move rearward if that makes sense.
Yes, you're absolutely right.

I'll begin (next time) with a good old chamber scrub then move on from there.

Thanks all.

Re: FTE / Hard extraction with AKM

Posted: Mon Nov 03, 2014 11:33 am
by snayperskaya
Out of curiosity what are the numbers on the base of your cases?, the ammo I'm currently using and have been for a while is 77 dated and not had an issue with it but had the hard extraction issue with 67 dated stuff.It could be some laquer "recipes" are stickier than others perhaps.

Edit....just used some of the missus' nail polish remover and took quite a bit of the laquer off a round.It might be worth trying this with say a mags worth of rounds and seeing if it makes any difference.If it does my money would be on the laquer getting instantly sticky on firing and "glueing" the case in the chamber rather than it being action related.

I know there's laquered cased .223 available so would be interesting to hear if any of the guys running .223 Saigas have had this problem or whether it is just the 7.62x39 variants.

Re: FTE / Hard extraction with AKM

Posted: Mon Nov 03, 2014 11:45 am
by SevenSixTwo
1984! :o

Re: FTE / Hard extraction with AKM

Posted: Mon Nov 03, 2014 12:24 pm
by DanTheMan
My Saiga eats milsurp cases coated with lacquer, however I have shot one of the newer Romy AK's from Oleg and that was a pig to extract, not as bad as the new straight pull VZ58's which need a brick on the handle to extract some cases. I think the chambers are just a bit tight, it's not the ammo.

Re: FTE / Hard extraction with AKM

Posted: Mon Nov 03, 2014 12:27 pm
by SevenSixTwo
It definitely seems to get progressively worse as the chamber heats up.

Re: FTE / Hard extraction with AKM

Posted: Mon Nov 03, 2014 12:33 pm
by snayperskaya
DanTheMan wrote:My Saiga eats milsurp cases coated with lacquer, however I have shot one of the newer Romy AK's from Oleg and that was a pig to extract, not as bad as the new straight pull VZ58's which need a brick on the handle to extract some cases. I think the chambers are just a bit tight, it's not the ammo.
Dan, is your Saiga a 223 or a 7.62x39?.I've owned two Saigas and never had this problem with either of them so as you said the Romanian chambers may be a little tighter but if that was the case I would have thought I'd have experienced it more often in the thousands of rounds its had through it.With both the Saiga and the Romanian there is quite a bit of blow-by as after a good range session of a few hundred rounds I get red laquer residue as far back in the receiver as the trigger group.

Re: FTE / Hard extraction with AKM

Posted: Mon Nov 03, 2014 1:21 pm
by snayperskaya
Just done a search on the 'net and the common consensus is that the problem is caused not by the laquer but by the build up of carbon due to blow-by, caused by steel cases not sealing the chamber fully.Some articles quote the problem occuring with very low round counts in chambers with tight tolerances.

From the 'net,

"There is a myth going around the internet and the US gun community in general that lacquer melts off casings and gums up the chamber of your rifle. This is not the case. Steel cases are made of a very mild steel which swells, but not as well as brass casings do. So, more gases escape into the chamber than usual causing additional carbon fouling of the chamber. Most western rifles like AR-15s, have tighter chamber tolerances than weapons produced in Russian and China. Cartridges start to get stuck in the chamber of an AR-15 once enough carbon builds up in the chamber over time due to the tight chamber tolerances. However, with a good solvent and a chamber brush, you shouldn't have any of these problems if you clean the carbon out after shooting the stuff".

So it could be the case that your chamber is machined to the "tighter" end of the tolerance scale whereas mine is looser and I experience the problem infrequently as a result, if that makes sense.

Edit.......just measured a case fired in my Saiga and one from the Romanian AKM and going off the measurements it would appear that the Romanian chamber is everso slightly tighter than the Russian chamber, which could explain why I've never had the stuck case scenario with the Saiga.

Re: FTE / Hard extraction with AKM

Posted: Thu Nov 06, 2014 7:32 pm
by RichT
I have a .223 Saiga and fire all sorts of laquered steel cases, barnaul and hornady, and have no problems at all, even when rapid firing and it gets hot, the only time when its slightly harder is using RG 5.56 surplus ammo?