AK SBR built using parts from five different countries

[Bret]

A few years ago I started gathering parts for a 7.62x39 AK SBR build. I wanted an Arsenal SLR-107CR, but was still mad regarding how poorly they treated me in regard to the unreliable SLR-106UR and SLR-106CR rifles that I had. So, I decided to avoid Arsenal and put something similar together myself. I started by getting a barrelless AMD-65 kit. Next I purchased one of the 12.25" 7.62x39 barrel assemblies from K-Var that has the integrated front sight and gas block. I also bought a US side folding stock set, Bulgarian rear trunnion side folding assembly, front latch parts and a Bulgarian side rail from K-Var. I don't remember exactly what I paid for all these parts, but I was able to get them at various times on sale, so I did pretty well. I checked the press fit of the Bulgarian barrel assembly in the Hungarian front trunnion and quickly found out that it slid right in. Also, the rear sight block on the barrel assembly wouldn't fit between the "ears" of the front trunnion. So, I had two problems. First, there was inadequate press fit between the trunnion and barrel journal. Second, even if I had enough of a press fit, the rear sight block wouldn't nest above the trunnion anyway. I went through a bunch of my kits and quickly figured out that the problem with the press fit was caused by the barrel journal being undersized as it didn't have a proper press fit in any front trunnion I tried. That was until I tried a virgin Yugo M92 trunnion. For some reason, the M92 trunnion has a slightly smaller inside diameter that would provide a good press fit. Best of all, the ears on top of the M92 trunnion are further apart than on a regular AKM trunnion. As a result, the rear sight block slid right between them. Problem solved! I purchased another M92 front trunnion off of GunBroker and had the serial number of the Hungarian kit engraved on it to keep everything matching. I bought a NoDak Spud NDS-1KP stamped receiver and had it custom serial numbered to match the Hungarian kit (yes, this was way back when they would do that). I had the receiver engraved with Hungarian selector markings. Finally, I bought a Bulgarian AK-74 gas tube, an East German AK-74 ribbed top cover, a Tapco single hook trigger group, a US gas piston, and a CNC Warrior Bulgarian style 24mm birdcage flash hider. Of course I had to get the stamp for the SBR too. I had intentions of building this rifle for a few years, but couldn't find the time. Plus, I had visions of screwing up the drilling of the barrel pin. I decided to sent the whole kit to Two Rivers Arms. Here's a picture of what went out the door.


Here's what I received back from Two Rivers Arms:




Not only does it look good, but the action is as smooth as glass. Everything fits like it was meant to be.

[Bayoublaster]

Very nice. I like the look of the gas blocks with the integrated sights.

[RetroRevolver77]

I still can't believe they didn't honor the warranty to replace your 106 rifle when clearly they had the wrong selector stop plates in them from the pics I've seen in your past threads.

7n6

[Bret]

I still can't believe they didn't honor the warranty to replace your 106 rifle

Well, they kind of did. They replaced the SLR-106CR with another that was obviously used and had a lower serial number. It didn't run any better. After that, they refunded most of my money for both. Ultimately, I would have been just fine with the refunds, but all the piss poor customer service in between was just too much to take. I think the rifles suffered from multiple problems, but I never knew what they tried to fix as they absolutely wouldn't tell me other than to say that the rifles have been repaired to my satisfaction. One problem that the rifles had was the bottom of the bolts being so wide that they'd strike the magazine feed lips as the bolt traveled through the magazine. I have several magazines that are damaged because of this. I don't know what they could do to resolve this issue short of installing a new bolt that was manufactured differently.

[RetroRevolver77]

Well, they kind of did. They replaced the SLR-106CR with another that was obviously used and had a lower serial number. It didn't run any better. After that, they refunded most of my money for both. Ultimately, I would have been just fine with the refunds, but all the piss poor customer service in between was just too much to take. I think the rifles suffered from multiple problems, but I never knew what they tried to fix as they absolutely wouldn't tell me other than to say that the rifles have been repaired to my satisfaction. One problem that the rifles had was the bottom of the bolts being so wide that they'd strike the magazine feed lips as the bolt traveled through the magazine. I have several magazines that are damaged because of this. I don't know what they could do to resolve this issue short of installing a new bolt that was manufactured differently.

The 106 bolt, carrier, and magazines were the same ones used on the SAM5 milled rifles which were their own NATO production arms. Were you using their magazines?

[Bret]

The 106 bolt, carrier, and magazines were the same ones used on the SAM5 milled rifles which were their own NATO production arms. Were you using their magazines?

Yes, I used the Bulgarian 5.56 waffle mags. I had the same thought in regard to the SAM5 milled rifles. The only thing I can think is that perhaps the stamped receivers on my rifles were not as square as they needed to be. If you measure the width of the bottom of the bolt and then compare it to the distance between the magazine feed lips, there's only 0.020" of clearance on each side. If everything's not perfectly straight, then the bolt will contact the feed lips. Here's a picture to illustrate the contact. The bright spot is where the plastic was worn off down to the metal.

Sometime it would stop the bolt/carrier completely. Other times I think it would slow the cycle enough to prevent the next cartridge from fully chambering.

[RetroRevolver77]

Yes, I used the Bulgarian 5.56 waffle mags. I had the same thought in regard to the SAM5 milled rifles. The only thing I can think is that perhaps the stamped receivers on my rifles were not as square as they needed to be. If you measure the width of the bottom of the bolt and then compare it to the distance between the magazine feed lips, there's only 0.020" of clearance on each side. If everything's not perfectly straight, then the bolt will contact the feed lips. Here's a picture to illustrate the contact. The bright spot is where the plastic was worn off down to the metal.

Sometime it would stop the bolt/carrier completely. Other times I think it would slow the cycle enough to prevent the next cartridge from fully chambering.

Wondering if they welded in the correct ejector rail. The issue from proto-type to production was standardizing what they had available- which at that time was 74 variants and 47 patterned milled variants. Remember the Bulgarians didn't exactly produce an AKM when this first went into production. Example the proto-type was built on an AKM pattern pre-ban receiver during the ban using the then imported kits for what later become known as the SA M5 barrel and carrier group. The post production guns were a combination of components from the 74's and the 47 patterned 5.56 rifles- so a lot of little details, such as the selector stop plate for instance- made a difference in how they performed because of the angle of the magazine in relation to the rails. They had to tweak what they had, once the 107's started rolling off the line, the only major differences were the bolts, barrels, selector stop plates, and feed plates.


7n6

[Campbell]

Nice build 😎