Diagnose and treat my AK malfunction

[Thin Black Line]

I have a new AES-10B (Romanian "rpk") w/ matching numbers, etc. It will
not consistently feed from the left-hand side of various mags (30, 40, drum,
metal, synthetic). The bolt and carrier seem to freeze up about 1/2 way
over the full mag. It can't be pushed forward at all. But, if the mag is
removed, everything usually goes forward w/o a problem. Sometimes you
have to pull back instead and empty out the round and then it cycles the
next round from the right side without a problem.

This malfunction is not consistent and in fact the rifle seems to work a little
better after it warms up. However, even warmed up it will still only works
well with a couple mags.

The action will cycle fine over any empty mag which I put into it. But again,
with a loaded mag, and dry cycling, with and without the recoil spring in
place, the same problem occurs. Gently sliding the bolt/bolt carrier forward
over a loaded mag w/o the recoil spring will still result in the same problem
and always from the left-hand side feed.

Any ideas besides a return to Century?

 

[Thin Black Line]

One more quick note: the mag well will accept the military bulgarian waffle
mags, but isn't wide enough at the front to accept the commercial bulgarian
synth mags (the ones with the cartridge pattern on the sides).

 

[Evil Monkey]

but isn't wide enough at the front to accept the commercial bulgarian synth mags (the ones with the cartridge pattern on the sides).

That doesn't mean there's something wrong with the rifle. The bulgarian cartridge pattern mags are like the equivalent of Pro Mag, but maybe better.

 

[briansmithwins]

If you can, check the height that the magazine rides at and the bolt rail height against a AK that works. I'd suspect that something funny is going on with the mag height vs bolt stripping lug height. Another posibility is that the trunion is damaged and not guiding the cartridges correctly into the chamber.

Post some pics like these:





If the receiver is built incorrectly the best fix is to return it to the manufacturer.

All this assumes you've had this failure with multiple mags and a clean rifle.

BSW

 

[equitytrader]

a clean rifle.

We're talking about an AK here, right? I'm not familiar with this term 'clean.'

 

[blkbrd666]

I would check several things:

Disassemble mag first and clean/lube. Check for any dents or distortion in the sides of the mag that hinder the follower moving less freely and any point throughout its travel. Check that the lips on the top of the mag are perfectly symmetrical on both sides and the one is not higher or lower than the other. Check for any gauling on the inside/underside of the left lip or on the follower. Check the opening between lips to insure it is the same width for its full length(i.e. both mag lips are parallel). Strongly suggest purchasing a new military mag(steel with the reinforcing rib down the back) to compare measurements and tolerances with the mag you are having problems with.

On the receiver: Check for any denting in the area of the mag well and the tightness of the mag when inserted. If this gun has the plates welded inside the receiver to hold mag in place rather than the oval indentions stamped on each side of the receiver, check them to insure they are not deformed, crooked, or misplaced before welding. With mag inserted, make sure clearance and positioning is correct by viewing through the ejection port or removing cover on top of receiver(you may need to compare with another AK if you have one, or one at your local gunshop). With bolt carrier removed, check your slide rails to insure the is not bending, denting, or other obstruction that could "slow" down the return of the carrier as it is picking up the next round.

If everything checks out visually, you may need to clean everything and mark all shiny areas of contact(this include top of the mag) with a black marker, reassemble and cycle dry by hand, then disassemble and check any points of contact that either shouldn't be there or are more pronounced in one spot than they are in another(this would highlight any areas of deformation.

NOTE: Start with the mag first...it's the easiest and cheapest potential problem to resolve.

Then DUH on my part, just realized you said "various mags", so you should probably concentrate more on the receiver being the problem(how mag fits it). Make sure when they ground out the mag well in the receiver, they ground far enough that receiver metal is not pushing against the mag body causing it not to seat correctly.

 

[Thin Black Line]

On the receiver: Check for any denting in the area of the mag well and the tightness of the mag when inserted. If this gun has the plates welded inside the receiver to hold mag in place rather than the oval indentions stamped on each side of the receiver, check them to insure they are not deformed, crooked, or misplaced before welding.

Good point. I'm leaning toward a couple different things working in
conjunction with one another. See more below.

I did some polishing of the bolt lugs and areas where they contact the
trunion and went back out to the range yesterday. I started with the
2 mags that usually worked well (both are used military mags --1 being
the romanian mag that came with the rifle). These functioned well as
did a couple runs with a 5 rd mag which started feeds from the right
hand side. The rifle was good and warm and at this point had no
problems feeding my entire chinese drum. However, a chinese drum
from another friend would not load the first round --same thing happened
with his 40 rd rom mag. Both had issues feeding from the left side. I went
back to two other 30 rd mags and loaded the working drum w/ brass case
fmj yugo ammo. Again, everything seemed to run better and we commented
that this rpk must've needed some "break-in" to shoot ok. Unusual for an
ak.

So at this point things seem to work fine, but then notice it's only working
consistently w/ fmj ammo. Tried to run some Russian hp and chinese sp
thru it and now it begins to smash the noses into the area right below
the chamber from the right hand side. So now it's not the bolt and
BC seizing up while feeding from the left side, but a the more common
smashed nose from the right side.

Yes, I'm leaning toward the internal welded side plates (there are no
dimples). There is also a large rivet from the scope rail on the left hand
side which is in the mag well. The receiver rails seem to be good with
no strange wear patterns going on. If anything there is less slop in the
bolt carrier movement than we had with standard rom AKs (this has the
rom heavy RPK receiver/trunion straight from Romania).

So could the mag well plates/rivet be causing a combination for the bolt
assembly seizing up as it tried to enter the trunion (before some wear took
it out) and the failures to feed non-fmjs?

 

[rbernie]

My experience with feed issues in a WASR have generally been with either the rear left carrier rail being malformed and catching the carrier in full recoil, or a misaligned gas pistol/carrier joint that slowed down the cycle. Either problem would cause the bolt to hiccup, and occasionally fail to RTB. The problem was worst with SP ammo, since the deformation of the lead nose on the feed ramp took some of the energy right out of the RTB cycle.

Does the rifle have a recoil buffer insert? If so - take it out and see if this clears things up. Also - do you notice a catch or hiccup in the action when you slowly hand-cycle the action?