If your going to build from scratch might as well use a Saiga as a host. Something very nice about having a matching russian receiver/bolt/carrier/barrel. I built a 5,56 krink on a saiga; wish I still had it.
I don’t look at the non-concentric bore as an issue. I don’t know of any AK nationality that consistently has concentric bores. Someone might get super lucky but I’ve seen examples of Saigas, Arsenals, Romy Gs, WASRs, that do not have concentric bores. The barrels are tough and work so I don’t care. If I want a suppressed rifle I’m going to go 300BLK.
I found the other issues when pressing off the FSB/GB and shortening the barrel. If you look at that theakforum post I have a picture there that shows the notches in the barrel for the FSB/GB. You can see that it was obviously mounted in two different positions. Neither were correct. The gas port in the barrel wasn’t as close to the middle of the gas port in the gas block as I’d like. The design of the hole and bevel in the barrel is designed to allow sloppy mounting and the holes not being perfectly lined up. But the instance I had wasn’t up to my par. So I mounted it with the two holes lined up as close as I could get them. Ensuring that rifle ran reliably(having plenty of gas in the system being part of it) was a main goal.
The rifle functioned before I did any modifications. So hard to argue with them. I look at any rifle I purchase as a project. This just added a couple of extra steps which I learned some valuable lessons with. That’s why I didn’t return it.
I just sold a SLR-107UR that I had for ~2 years abd just never got around to SBRing.
It’s almost ideal as SBR fodder. You pull the FSB, pull out the metal restricting disk that inside, have your smith cut and crown, and reinstall the FSB. Refinish if necessary, add a Bulgy muzzle booster* and you’re done.
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*K-Var has them for $99, before they were back in stock real ones were rarer than frog fur.
Mine had (1) and (2). I just got it engraved. I guess that I will find out if it has (3) when I chop the barrel off.
SLR-107UR’s are going for $1700+ now, so you’d be at $2000 when all was said and done. If you want a 7.62x39 krink, building a Yugo M92 with a sidefolder would be a more cost effective option. It would be only slightly more front heavy.
If the original krink 5.45x39 cartridge will work for you, then building a Russian krink on a 74ULLC receiver with a Bluejack barrel would be the way to go.
Here’s my video on removing the FS/GB from my SLR-107UR.
http://www.youtube.com/watch?v=R3p3mC_hbeM
I’m going to video drilling the FS/GB , repressing the FS/GB, cutting the barrel, and crowning the barrel.