Mods, feel free to lock my old thread. I wanted to bring this front and center. I see another member with concerns and I would like the opinion of people who have shot alot.

@AtlanticFirearms
@mrgunsngear
@Militaryarmschannel

And to Rob Ski if you read this, you guys have shot and reviewed alot of AKs over the years. Just curious for y'all's opinions.

200ish rounds on my KP57 SLR 107r.

Attached File


My main concern is the lug on the bolt.
Before shooting it was perfectly squared off on the corner where you can see it has contacted the trunnion.

There is also a little more play in the bolt( vs my Wasr) as it rides in the carrier in the gun, I imagine that when it picks up a round that lug is slightly lifted and slams right into the trunnion.

Attached File


Making the contact here

Attached File


Plan on buying 500 more rounds to blow through to see what happens. Or should I send it back? It did have 5 fail to feeds because of a crappy old magazine or so I thought.... It could have been because the edge of the trunnion was squared off and it started feeding because it peened into shape. My main concern is damaging the bolt. Opinions?

Trunnion beforehand
Notice how it is perfectly squared on that bottom corner.

Attached File

so is the fix to just file down that part of the trunnion? My kp57 isnt experiencing the problem but if it was wouldnt that fix it?

I thought about taking a file to it, I might do that when I get home.

I don't own an Arsenal, but I do have an opinion here; from what I see in the pics, these wear points are not normal. Will if affect the function of the weapon? Probably not, according to Arsenal customer service (from what I've read). Will it affect the perception of Arsenal's reputation for above normal quality of its products at an above normal price? Yes, particularly for the owners of the affected models. Will it affect the reputation of Arsenal's products for prospective new customers? It has mine... to an extent at least.

Something is out of spec on these affected models and apparently Arsenal is not admitting to it... yet. I see no reason to use a file on the affected areas. Just do what Arsenal says and let it wear on its on, since they say it is not a problem to begin with.

yeah i doubt it will affect the function at all, ive seen AKs with a lot more damage than some trunnion peening that were still kickin out lead like nobodies business.

arsenals response to the problem however...kinda pathetic really.

I bought two of the slr107s last week, got consecutive serial numbers, keeping one and selling the other to pay for an sr25 i impulse bought, if i were buying again id probably just get a wasr.

If you file on it, you throw any chance of a warranty out the window

Reading an files it seems the fix is to just file it down and it operates like normal.

Yeah thats a retarded dilemma, Arsenal says it's not a problem in their statement, let the lug beat the trunnion into shape we ain't taking it back. But if I fix it myself I void the warranty

Don't file on anything. I don't care what Arsenal says. I've owned AKs since 1982 and fired more rounds through AKs than anyone at Arsenal U.S.A. I have one and in some cases two of every AK that has ever been imported. I have a PolyTech Legend with a little over 100,000 rounds fired and the trunnion isn't  smashed like yours. AKs don't smash themselves into spec. Go watch Rob Ski's video about his WASR with over 10,000 rounds. The trunnion on it doesn't look like yours either. People saying to file on stuff don't know AKs. They're either in spec or they're not and yours clearly isn't in spec.

You do what you want but filing on stuff isn't correct. Arsenal should take the rifle back and give you a refund or another rifle. I doubt that will happen because their CS sucks.

Well, a polytech legend doesn't have trunnions as they are milled receivers.

OP, I would do any gunsmithing on a brand new gun.  Were all FTF with the same mag?

Yes on the mag.

I would chalk that up to that mag then.

Is there a lot of wear on the bolt carrier?  Look like paint is being removed from the top and side in the pic.  Could be flash though.

Just on the lug.

I just looked at a few of my 74s and I think the issue boils down to your bolt not being chamfered.

Here are the trunnions

Thanks for the pics of the trunnion. I think it'll probably be fine now that it's made it's own chamfer.

Yes that seems to be the issue. I posted about it in the other 107 thread, and it has been mentioned by several over on AKFiles.

Additionally one person on AKFiles had the carrier making marks on the top of the shoulder because the radius machining on the carrier face was incomplete.

Seems like arsenal machinists missed a checklist.

The positive is that adding that chamfer to the bottom edge of the shoulder takes 5-10 min.

Bolt from one of the above guns


And one from another parts kit

That looks to be exactly the problem. The lugs on this batch don't seem to have that. You would think Arsenal would send out new bolts at least

I really think that is their thought. If you look at mine there is some slight damage because the bolt can ride up an hit the trunnion but the chamfer guides and minimizes the damage to the bolt and trunnion.

Look at all the other cost and labor steps that have been eliminated in the AK line from start of production until now. You just purchased one with another one eliminated.

Cowboy boots?

Well, a new bolt would need to be tested for proper headspace. Don't want to change one problem for a bigger one and a possible kaboom.

Boots and forgetting headspace, I need to take my ass to bed. Lol

put another 700rds through my mp57 today.

only a slight bit of wear in that area, 99% cosmetic, 1% looks like the bolt might have hit the trunnion a couple times, nothing to cause concern though.

Yeah I think mine will be fine, I doubt it'll ever cause any issues.

Im one of the ones from the files that fixed his, just didnt wanna fight with arsenal over this, they are a real pain in the ass to deal with esspeacially once they have your rifle, they could care less when you get it back, Putting a slight chamfer on the bottom of the bolt lug guide on that left side of the trunnion took 10 min with a needle file and to smooth with an india stone, I blued the area to check for any more progression of  the issue and have 1000 plus rounds now through the weapon, The blueing isnt even effected. Easy stuff and this rifle is a beast man.

Thanks for sharing, I've read that thread over there. I'll probably end up doing it just like you guys. I still love the rifle and don't want to deal with arsenal either.

^^You will be better off in the long run