I have always read/heard that the AK top cover is too unstable to mount sights and or optics. Yet, the Galil seems to have solved this problem since no one complains. I have an original IMI Galil ARM and I never noticed and shifting in POI due to the rear sight being located on the top cover. Also, all the "Krinks" have their rear irons on the top cover and I havnt heard any complaints, although I hear very little accuracy evaluations from such guns.

The other day I was shooting my ZPAP M85 pistol (with the hinged top cover mounted optics rail and rear sight) and was getting some crazy POI shifting of up to 10MOA with both Aimpoint and open sights. I was freaking out. I thought my Aimpoint busted lose but then when using just open sights, it was also doing the crazy shift in POI.

I'm not sure if I closed the top cover wrong since it seemed rock solid as usual with zero play. Maybe something is "breaking in" on this fairly new gun or maybe I'm having a stroke.

I went back yesterday to try and repeat the problem but couldnt. I'd fire a group then open the top cover, remove the main spring, move the bolt back n forth then put everything back...then fire another group. I could not discern any major POI shift that I wouldnt normally get using irons or RDS with my old eyes (my best groups are 2MOA but typically run around 3.5-4MOA with good ammo). I did this at 50 and 100 yards. Now, I'm also very careful to check the top cover to make sure it is locked in proper and tight. There seems to be 5 points it locks in:
The front hinge which moves freely to open and close the cover,
The rear where it mates up with the mainspring detent that pokes out the hole in the rear of the top cover,
Both sides of the top cover in relation to the receiver,
The front left side where the bottom of the top-cover mates into a matching recess in the front trunion's left arm (not sure if this is all models or just a nice feature on the ZPAP).

So my question is: Does anyone else check the accuracy of their AK pistols? Have you noticed any POI shifting after opening and closing the top cover (to add oil or clean the gun)?

I’ve been keeping track of your post to see if anyone would chime in. I wanted to make a comment regarding what you said about your Galil. I myself recently had a Galil ARM assembled on a Tortort receiver. My top cover was a bit wobbly and that coupled with other issues kept me chasing my zero which was extremely frustrating. It’d never have held a solid zero until I figured out a way to tighten up the fit of the top cover. That experience has made me eternally suspect of top cover mounted sighting systems.

My AKS-74U doesn't seem to shift at the short distances I have used it. I installed a KNS piston and the process to dial in the gas means you are opening the top cover a lot. The Texas Weapon Systems cover I had on one of my rifles seemed to hold zero, but I didn't do any extensive testing. I still hit targets about where I wanted at 100 yards with it. My Galil seems to move around when I remove the cover, and it is really tight. I can still hit targets under 100 yards without too many problems. I'll have to work on it a bit. That is my experience with removeable top covers on AKs.

I bought a mount for my m85, didnt install and drill my top cover because it didn't seem rock solid. I'm going with a ultimak

As crazy as this is going to sound, I have a PSA AK-P with a Primary Arms red dot mounted on a hinged cover. It's insanely accurate with Wolf ammo. I have opened the cover, moved the red dot, leaned it over and it slid forward dropping on the carpet. Not fixing what's not broke.

Attached File

At what distance though, repeatable at 100 yards?

Thanks for the replies.

I know most people only use their AK "pistols" at maybe 25 yards but I've shot my ZPAP M85 out to 200 yards. The gun has potential for decent accuracy and I've gotten some 2.25MOA groups with ammo that it likes (69gr Matchking). Normally, using irons, I probably wouldnt be able to tell the difference of a few MOA shift in POI but with the optics rail and the mounted Aimpoint, I can get groups good enough to see a potential shift.

That ZPAP M85 has the most solid top cover that I have seen, almost zero play and more solid and stable than my Galil.

I have continued to look for POI/POA shift caused by the top-cover mounted optics.

I would set up targets at 100 yards, fire a 5 shot group with a good known accurate load. Optic is an Aimpoint H1 attached to the rail on the top-cover. Then open the hinged top-cover, remove the recoil spring, move the BCG back and forth then replace everything. Then fire another 5 shot group at 100 yards, same ammo, at a new target and compare the POI.

I HAVE NOT BEEN ABLE TO FIND ANY POA/POI SHIFT MORE THAN 2MOA. I believe that any POI shift that I thought was occurring was due to a combination of my old eyes coupled with my RDS' 4MOA dot blooming and parallax caused by different head/eye position from shot to shot.

I now consider mounting sights and optics on the hinged top-cover solid and not effecting accuracy to any practical measure, at least on the Zastava ZPAP.

https://www.atteroarms.com/product-category/ak-optic-mount/