AK barrel replacement

[CGRifleman]

Has anyone here replaced the entire barrel assembly on an AK? What all does this involve?

 

[Sam1911]

I've built several, so I've pulled and reinstalled the barrel assembly.

There is a large pin through the front trunion that locates the barrel and sets headspace. You'll have to push that pin out and then press the barrel out of the trunion.

Press in the new barrel, set the headspace, and mill/drill a new pin channel in the new barrel. Drilling that pin channel through the barrel tang is going to be the difficult part, but with a good mill it isn't difficult.

 

[Tirod]

How many ton press, and does it need to work with the length of the barrel, or does it capture a shoulder on it and the receiver?

Obviously a headspace gauge is required, and that means checking with the bolt locked.

Is the barrel splined, can it be cocked off vertical? And once set, what jigs are necessary to hold it while milling?

It doesn't sound like kitchen table frankengunning, more like traditional gunsmithing with a fully equipped shop.

 

[Sam1911]

How many ton press, and does it need to work with the length of the barrel, or does it capture a shoulder on it and the receiver?

One I did with a hammer.

One I did with a 20-ton shop press. The trick is making an extension long enough to press against the breech face (when pressing it out) through the receiver. Not an issue if you're building off a kit with a cut-up receiver. Pressing it back in is no big deal as you can set the trunion against the press arbor plate and press against the muzzle to seat the barrel.

Obviously a headspace gauge is required, and that means checking with the bolt locked.

Yes. Though a lot of home-builders just use a live round with a layer of masking tape on the case head. Press, check, press a little more, check. Press it back out a bit, check. When you get the right headspace, drill the pin hole.

Is the barrel splined, can it be cocked off vertical?

Nope. Round peg, round hole, but the rear sight block will key into the trunion so you can't be too far off. I still sight it to make sure it's centered well. (Once seated, though, it couldn't be more than something like 1/2 a degree off -- close enough for an AK.)

And once set, what jigs are necessary to hold it while milling?

None. Once the barrel is pressed into the trunion it will be tight enough to hold itself still while milling the pin hole.

It doesn't sound like kitchen table frankengunning, more like traditional gunsmithing with a fully equipped shop.

Milling the pin hole is the only touchy part. I -- literally -- built my first one with a 3-lb hammer on my garage floor, years ago.