I have a KR-9 and want to shorten the barrel to KR-9 SBR specs. I have the tax stamp so I’m not looking for legal advice or trying to do anything illegal. My original thought was to wait until I was moved and had a lathe again, but that’s still a ways off. I was poking around their website and the KP-9 barrel is pretty inexpensive. So now I’m thinking that it would be much quicker and probably not too difficult to change the barrel for a KR-9 to a KP-9. I used to heavy into off roading so I have a 20 ton hydraulic press, which seems to be a good way to remove an AK barrel.

Before I commence tearing down a KR-9 what kind of possible mine field am I stepping into?  Help is always appreciated.

Thanks. I should be able to solve that, though I’ll have to get the GO/NO GO gauges for 9mm. I have a milling machine so it shouldn’t be a problem, but working on AKs is new to me.

Removing ak barrels is usually simple. Press out barrel pin. Press out barrel. If the barrel hasn't already been drilled for a pin, just put the barrel in and get the correct length for headspace using incremental bracketing. Then, after you have a go, mark the location on the barrel for the pin. Drill. Pin. Double check with gauge. Done.

That seems pretty simple. I have what appears to be an important tool for working on AKs, a 20 ton hydraulic press and the ability to watch what I’m doing so I don’t break things…normally. Locating the place to drill on pin it I can do on my mini mill.

Does removing and changing the barrel on a KR-9 involved removing the reunion as well?  I know that at least part of this sounds like stupid questions, and while I went to school to be a gunsmith I’m a complete FNG on the AK platform, short of basic maintenance. Thanks for all of the help.

Push the old barrel out, push the new one in and headspace it, drill for the pin, populate the new barrel and go. You might need to make a tool to push the barrel out. I always use brass on the breech face.

Just remember the KR/KP-9 uses a unique barrel pin .....like the Vityaz, that is extended on one side and provides the surface for the stock to latch to when closed.

If you press it in too far, you won't be able to latch your stock.

There are no "oversized" pins available.

That’s important to know. I have the tax stamp, I have the short barrel, but it doesn’t look like I can buy the pins if I screw one up. And I can’t find a decent schematic, though Kalashnikov USA does sell a schematic in the form of a cleaning mat.

So is there one direction versus the other that would be a much better approach to this, or does that part matter?

I ended up SBR'ing my KR9 at home with hand tools and a 12 ton press. There was a good investment in tools (Annular cutter + pilot, facing cutter, crowning tool, threading die + pilot), but it came out perfectly. The hardest part was removing/repressing the FSB. The pins came out easy, but the FSB was tight .....

I would advise having your existing barrel pressed out, cut/threaded, then reinstalled ...... rather than buying a new (virgin) bbl ..... no headspace issues, no cutting of grooves for the bbl pin, RSB pin, FSB pins, or handguard retainer ...... just pay close attention to the distance your bbl pin protrudes from the (L) side of the trunion

Did you thread the end of the barrel AFTER it was back on the gun?

With the choices you have, how did you re crown the barrel. Wondering why you as much as how.

DB

I never removed the bbl ...... just the FSB.

Crowning is easy .....just need a facing cutter & 9mm pilot, and a crowning tool. Use the annular cutter + pilot to get the OD correct, then thread away.

In 25+ years I've never pulled an AK bbl just to thread it ..... nor have I ever had a concentricity issue with the threads I've cut.

You'd probably need to make some custom blocks to press out a KP/KR9 bbl just due to the differences in the chamber area, and the fact the magwell gets in the way