For those that aren't aware, many who've received the latest batch SLR107R's with serial prefix KP57 are having premature wear issues, mainly on the left side of the trunnion. I was made aware of this by an AKOUL Facebook post on Sunday (Can't find the post to link it, sorry.) That post was then followed by a reply today from Arsenal (Which I also don't have, sorry) basically saying that it's because of two different metals impacting one another and that once broken in eveything will be dandy. Bullshit.

I ordered mine from Kvar in December and received it about two weeks ago. I was planning on taking it out for the first time today but, I read the post on AKOUL last night and decided not to. I did, however, decide to hand cycle it about 40 times and guess what? Premature wear has occurred on the left side of the trunnion. Nothing crazy, but more than enough to be angry at the $850 pos you just bought. My SGL-21 has a few thousand rounds through it and is still in perfect condition around that area. What should I do? I've never dealt with them but, after reading the post they left in response to this problem, it sounds like Arsenal is plain skirting the issue.

Saw that also. From Arsenal's facebook page about it:

"On Sunday, January 28, 2018, Arsenal became aware that an internet blogger posted concerns regarding “premature wear” in the Arsenal SLR107R series rifles.  Arsenal has reviewed the issues raised by this blogger and have found that the concern is based upon what appears to be wear on the trunnion at the point it makes contact with the bolt.  These issues do not appear to create any safety or reliability issues.  Rather, this is caused by two different metals impacting one another and, once broken in, there should be no issue.  Each firearm is unique, and some may have varying sizes with respect to the clearance chamfer on the trunnion block.  As such, there will be some firearms where the chamfer will initially make contact with the bolt. Again, once broken in, the bolt will perfectly align in the chamfer for a consistent and reliable fit going forward.  Arsenal stands behind its firearms and, if you have any questions or concerns, you are welcome to contact Arsenal customer service."

Not sure what I'd do with it. Kinda interested to see how many pop up with more issues.

Actually, Arsenal ' s explanation sounds reasonable to me and the issue may well be simply cosmetic rather than anything that affects reliability or safety at all.

Seriously; if it were my rifle I'd just shoot it while keeping an eye on the area of concern and checking to see if as Arsenal says, the parts will just wear in.

The internet has a way of driving misplaced hysteria.

"Each firearm is unique" goes against assembly-line manufacturing ideals.  Every firearm of the same model should be nearly identical (within specifications for tolerances, of course).  Their explanation seems to be that it isn't quite within tolerances but will beat itself into shape soon?

Got any pics of the premature wear?

I don't own an Arsenal firearm, but have read a lot of good things about the company and their products. But if they are like most other firearms manufacturers, unless the product is completely broken, or a major failure occurs, you will not get any satisfaction from their customer service or their warranty; or at least not until they get so many complaints, their arm is twisted into submission and they respond to the issue. They are not going to do the right thing out of the goodness of their heart. Evidently, the firearms business is a rough and tumble business, for the most part.

They only care about their reputations until it cost them something...

Just my .02

I've been talking with an owner of one of the affected rifles over on reddit. The issues seem to be a combination of two things

1. Insufficient chamfering of the left side locking lug on the bolt. The top and bottom of the front side of the locking lugs should be chamfered specifically to prevent the lugs from contacting and catching on the trunnion as it rides off of the rails and into the trunnion

2. The carrier bolt stem channel and bolt stem itself may have a bit more play than usual. The owner said that his bolt wiggled in the carrier more than other AKs he had. Unfortunately he did not have calipers to check. For reference, the bolt stem diameter should be 0.429" and the carrier stem cavity should be 0.442".

I would check your bolt and carrier for the above issues.

The wear mark also looked like the bolt was beginning to rotate too early - this owner confirmed that his bolt was NOT rotating.

I really like Rob and his channel but there seems to be a lack of mechanical understanding or ability there. I wish he would do some investigation of his own instead of just posting surface wear pics and freaking out about them.

I can take pics but, I don't have an anywhere to upload them to. Suggestions?

If you can upload them to your PC or use your smart-phone, you can create a free membership with Imgur. That is the one I use. Once you have an account/login with Imgur, you can upload/drag-n-drop your photos to Imgur. Then, you can open the photo on Imgur, right click and copy the URL address (which will end with jpg) and use the image uploader here on the AR15 forum.

Good luck.

Good info. So, Arsenal is saying the wear is being caused by two different types of metal contacting one another and breaking in, which may be correct but, if that's true then why isn't it happening in the other side of the trunnion? From the pictures I saw on that Facebook post from AKOUL, there were some fairly big indentations on the left side of the trunnions of some of the guys who had fired theirs. Your answer seems more plausible. As far as the bolt having more play than usual, I also got that feeling when I first looked at it but, thought it was my imagination. I'll pick up some calipers and check it out.

What I'm starting to understand though, is that I'm going to get nowhere trying to get Arsenal to exchange my possibly defective, un-fired rifle for a replacement unless, there are enough people with the same problems. If that's the case, I'm going to go put a few hundred rounds through it and see what happens. I'll also have my gunsmith check it out.

Okay, I'll try to get around to it. I'd rather post pics after I've fired it. If you're wondering what it looks like though, just check out the Facebook post from the AKOUL. It's similar to those, minus the indentations or the way it looks like the metal is peeling.

Basically.

Images of the damage on trunnions.   No pictures of bolts.

Sorry, that just doesn't look right to me, even if it is an Arsenal. None of my AKs have that kind of wear.  And how can they say it will get better with more wear? Something just ain't right...

I've seen a few AKs (and own a couple like this) where the bolt hits part of the trunnion as it leaves the rails, and leaves a small indent or friction wear. Both on the left and the right lower sides.

But this is the first ones I've seen with that large mark on the left upper side of the trunnion, and this mark is large enough that there doesn't appear to be enough mechanical "slip" for the parts to eventually wear in.

I really do suspect that the problem comes down to excess bolt play. Depending on which part is out of spec, it could mean bolt or carrier replacement.

I'm also curious about the chamfering of the front of the bolt lugs. Anyone want to post a front pic of an affected 107R bolt?

I don't have a 107R so this is all speculation.

That is not normal wear and Arsenal's reply is BS. I have several very high round count AKs and none show wear like the pics above and the other photos posted elsewhere. For Arsenal to even reply the way they did is wrong. I've read some stupid replies from other people as well like file the damage or don't worry about it keep shooting it.

He'd have to form an AK mechanical engineering union instead of an operator's union.

I'd like to point out that the issues above are impossible according to Internet wisdom, because Arsenal is a former-Combloc factory that uses the Soviet tooling and training the Commies invested so much money in and got so right instead of reinventing the AK like US manufacturers had to do.  So, I'm sure this wear is all in your imaginations - unless the Internet is wrong.

Damn, how does that even happen? Does the bolt move side to side when in battery? I would definitely be bitching to arsenal/kvar to replace it.

I have 40 rounds thru my SLR-107, prefix KP57. I have similar and milder, not identical, trunion contact wear. My bolt stem diameter is .427-5 (not 429) and my carrier stem cavity provides several readings ranging from .441-443.
I recognize that an AK is riveted together and lacks a certain level of precision, but it really bugs me that my front sight has a very slight cant. In a new Arsenal, that is just wrong! My new WASRs aren't canted. It appears that my new 2107 WASRs, while they feel slightly rougher than the Arsenal, cycling manually, they are certainly of equal, if not better, quality. Ain't that an unexpected bitch!)
Kudos to WASR and well, __________to Arsenal.

It is what it is. They're not building rockets and they obviously believe that perfect is the enemy of good. The problem is that they need to achieve good before they abandon any efforts to be perfect.
File, cold blue or Alumahyde II and don't sweat the small stuff.

Not to get too far OT here, but one of my Saigas had a slightly canted front sight block, and rear sight block. The gas block was straight in relation to the top of the receiver, which was my reference point. The front and rear sights were canted to the left about the same amount. If you looked down the barrel, it appeared that the gas block is what was canted, but it was actually the front and rear sights.

I've read that it is not uncommon for an AK to have canted sights. That doesn't jive with my OCD. So, I removed the pins from the rear sight block and front sight block and clocked the sights to align with the gas block and top of the receiver. Didn't have to move them much, but now they are as straight as an arrow, and in line with the gas block. It took some effort, but I feel it was worth it to me. I like the improvements in the fit/alignment of the sights.

I suppose it just goes to show that even the most expensive and best examples of the higher quality AKs can have issues.

i put 1200 rounds through a kp57 today and have no issues so far.

Maybe not all in the batch are bad?

That would be great news and I hope your good luck continues.

I put 150 rounds through mine today and no big chunks have been taken out of trunnion, just a small indentation and surface wear. There's also a good bit of surface wear on the bolt in general but, I can't seem to find any deformations. There's a portion of the bolt face (Not sure if that's correct) where about 80% of the finish has been removed. IMO, the wear is unacceptable for a new Arsenal AK but, it pales in comparison to the AK's pictured above. I still don't know what to do with this thing other than keep shooting and see what happens.

I'm not certain, but I believe that the 107s are actually  built in Las Vegas with parts manufactured by Arsenal in Bulgaria rather than being assembled in Bulgaria.

Arsenal Las Vegas keeps exactly what amount of assembly  is done where, under wraps I think.

Could you guys with affected 107R rifles check the bottom leading edge of your trunnion's carrier stop shoulder? I suspect that Arsenal may have missed a chamfering step here.

Looking at photos of another owner's affected trunnion, the trunnion appears to be missing any chamfering of this edge whatsoever - the bottom edge of carrer stop shoulder, where the bolt enters the trunnion, has a hard edge to it.

Every AK that I have (incl. Bulgarian) has the hard edge of the bottom of the carrier stop shoulder chamfered here. Along with a chamfered edge on the top of the bolt left side locking lug, these two chamfered/angular surfaces should guide a wayward bolt head into the trunnion channels.

My highest round count AK (WASR, 8k+ rounds) has a light indent in the same location as the affected 107R, but significantly less than any photo I've seen. Additionally it is evident that when the bolt strikes here (most likely due to carrier slop), the two chamfered edges meet and nudge the bolt back into the correct path in order to enter the trunnion channel.

I suspect if Arsenal did not chamfer this edge, the bolt may leave a more significant impact mark on the carrier stop shoulder, as there is only one chamfered surface assisting the bolt back to the correct alignment - the bolt head is moslty hitting a flat surface with a sharp edge.

If the chamfer is missing, it's an easy thing to correct.

I do not have a 107R so this speculation only based on looking at other owner's photos by request and comparing them to other AKs that I have

Received a reply from one owner that the bottom edge of the carrier stop shoulder is, in fact a hard edge with no chamfered surface.

By comparison here are a WASR and M92 trunnions. You can see the chamfered edges on the bottom of both carrier stop shoulders. On the WASR, you can also see where the bolt has occasionally hit the trunnion in a similar way to some of the pictured 107Rs (it has a sloppy bolt), but the chamfered edge guides the bolt back down into the trunnion channel.

Seems like this is not normal for the chamfer to be missing, but 107R owners outside the affected serial range should be able to confirm.

WASR - ~8k rounds;


M92 - ~1k rounds: