I know that these rifles can have both overgassing issues due to having the original spec gas port on a 16" barrel, and the feeding issues that early 106 series rifles can have. However, I can't really pinpoint if my issues are coming from the feeding problems these had, or if my rifle is so overgassed that it's causing ejection and/or feeding issues. Have mostly used brass M193 spec 55 grain ammo during the short time I've had the rifle.

I've used a variety of the Circle 10 smoked clear mags that I believe are gen 2 (20 round and 30 round), as well as the reinforced black Circle 10 mags. I do also have some Polish 5.56 Radom mags on the way as well.

It seems that spent cases either aren't clearing the rifle, or are hitting the dust cover and getting pushed back into the receiver. Usually it ejects them with the typical authority of an AK, but sometimes it'd just 'puke' a spent case out and land pretty close to my feet. I could also take the dust cover off and not have nearly as many FTE's as than when the dust cover is on the rifle. Cycling by hand, it seems that ejected rounds will eject upwards around 1 or 2 o'clock (12 o'clock being straight up). Successfully ejected cases are dented in the middle pretty badly, much worse than I remember my Arsenal 106FR doing (which ran very reliably).

I did try a mag of some steel Tulammo .223 with much better results, but I did have one strange feed malfunction where the round was straight and halfway into the chamber, but the bolt just kinda stopped halfway. I pushed it shut with the palm of my hand and it went into battery.

It does have the dreaded "AB 47" serial prefix, but I've also heard that can be hit or miss in determining its manufacture date.

Thanks

Pics:

In case anyone was following, turns out it was overgassed pretty bad. Recieved and installed my KNS adjustable gas piston and the rifle works great.

IT sounds like you solved the issue but here is some background info

5.56 out of an AK routinely will hit the dust cover. So will .308. The tapered case rounds seem to have less of an issue with this. If you look at the NATO-caliber Valmet variants, they even added a rubber shell deflector to the dust cover at some point.

Another thing that happens is that the carrier charging handle will often come back and smack the spent case as it is ejecting, and this can be exacerbated by timing issues caused by either a recoil spring out of spec, or the rifle being overgassed - maybe even both. It's possible for the spent case to hit the dust cover, thereby taking up some of its energy and causing it to "hang" there for a second, then get hit by the carrier charging handle, and get knocked back into the receiver. I would almost bet that this was exactly what was happening with yours.

A dent in the neck is from hitting the dust cover. A dent half way down the case itself is from being hit by the charging handle.

Of course being overgassed severely can potentially also cause the extractor to let go prematurely due to violent extraction.

I have a video of myself shooting a 5.56 74 build where the ejection pattern can be seen. I've watched it in slow motion and a few times you can see the rounds almost bouncing back into the receiver.

Changing the gas pressure or recoil spring strength can significantly effect the ejection pattern, as you've discovered.

which piston did you purchase? I just picked up an slr 106cr. have not shot it yet. anticipating over-gassing issue.

what piston did you go with? agp-a-20s or 20L?

This thread is 4 years old. I don't think KNS even used that model naming system when they introduced their adjustable pistons.