Pressing barrels

[bodiebill]

I am a first time builder going to San Diego Party in Jan 2011.
My kits are Romy G less barrel. Have two unused Romy G bbls that will need to be pressed into the trunnion, then headspaced.
What special equipment, tools, lube, dry ice etc. should I bring to the Build Party?
Do you freeze the bbl and heat the trunnion for fitting?
Any tips would be helpful so that I am fully prepared.

[ae13291]

use a caliper to measure the trunion inside diameter and the chamber outside diameter, make sure they are .001 or .002 apart and polish up the pressing areas.

[tujungatoes]

Are your barrels bare/virgin romy's? If so you should really think about sending them to a pro(turbothis, restorit1,...isn't slamfire51 doing these too?) to have it setup and headspaced before the party. It's not too expensive, and you get a build that's goes as smooth as possible.

also...

• Only bring a kit that has an ORIGINAL UNCUT barrel also a matching numbers kit is also recommended.

Enthusiast's rules aren't written in stone, but the intent is to streamline the BP so everyone leaves with a functional rifle/pistol. We can solve headspace problems(to an extent) at the party, but it's fairly time consuming to setup a barrel from scratch. As a first timer you really should try to eliminate as many problems as you can before the party.

[bodiebill]

The kit was without a barrel.
The barrels are complete and unused Romanian-made, taken from Romanian rifles which were then converted to .460 caliber.
They are not "virgin" bbls.
They will also need the rear sight base, gas block and front sight pressed on.
As I understand the process, head spacing is done during the bbl pressing stage.
I will be bending a flat receiver at the Build Party so all of this must take place after the flat is bent and trunnions riveted in place.
Am I correct?
Thanks

[tujungatoes]

Ok, if it's a takeoff barrel that just needs to be populated that's not so bad. It's still more work, but at least you have all the pin slots cut already. Should be a slam dunk. I'd actually recommend populating the barrel before the party if you can. there is no need to do it after the receiver is together, since all the alignment is already done for you.

the biggest problem you might have is headspace. It's kind of a crap-shoot. Most likely it'll be fine, but you're not gonna know till you put it all together. If it's too far off you end up drilling and reaming for an over sized pin. As far as I know it's not something any of the regulars are set up for(yet).

[SKSer]

I freeze the barrel overnight and heat the trunion in the oven at 500 degrees, it really does make a pretty big difference.

[chiz]

I just finished head spacing a virgin barrel on my AK74. It took me about an hour to finally get it right. You have to press the barrel a little bit at a time and keep checking it. If you go to far you need to press it back out a little and check it again. Its not hard, its just time consuming

[SJgunguy24]

Ok, if it's a takeoff barrel that just needs to be populated that's not so bad. It's still more work, but at least you have all the pin slots cut already. Should be a slam dunk. I'd actually recommend populating the barrel before the party if you can. there is no need to do it after the receiver is together, since all the alignment is already done for you.

the biggest problem you might have is headspace. It's kind of a crap-shoot. Most likely it'll be fine, but you're not gonna know till you put it all together. If it's too far off you end up drilling and reaming for an over sized pin. As far as I know it's not something any of the regulars are set up for(yet).

Be careful with that. Remember everything comes off the headspace. If the barrel headspaces at a different spot and you need to fill and redrill or use an oversize pin that can throw everything else off. There could be a problem with everything lining up, it's rare but it's happened to me before. Sometimes I'd rather have a virgin barrel so at least if something does go wrong it's me who did it.

[Roccobro]

The kit was without a barrel.
The barrels are complete and unused Romanian-made, taken from Romanian rifles which were then converted to .460 caliber.
They are not "virgin" bbls.
They will also need the rear sight base, gas block and front sight pressed on.
As I understand the process, head spacing is done during the bbl pressing stage.
I will be bending a flat receiver at the Build Party so all of this must take place after the flat is bent and trunnions riveted in place.
Am I correct?
Thanks

Chances are the head space and pin location WILL be different. No two AK's are built identical. Unused barrel or not, it was NOT headspaced in your trunion. As*Uming it will be fine will invite Mr. Murphy to your party.

If this is your only shot at a drill press and 12t press, buy a much larger oversized pin, drill bit and (hopefully) reamer. If it is wrong you won't be there trying to figure out what size is minimally necessary to make it right. All the while others are popping their matching number kits together and test firing them.

I don't freeze the barrels or heat anything on install. Just using the right tools, technique and material do it for me. If it needs freezing and heating, you prolly have something going on that needs addressing first. But you'd know this before trying if you measured it all. OR not worry one bit if it is a numbers matching as Enthusiast recommends*.

Be careful to not ruin the HT on the trunions by firing them up too hot too.

Justin

[4thSBCT]

I agree with Rocco, Freezing and heating your parts is unnecessary. Just go get some molygraph or other high pressure lube. A pair of 20 dollar Harbor frieght digital calipers are nice to make sure your parts will have the correct press fit. Here's an E german build I did recently on a virgin Romy barrel. After measuring, the gas block area on the barrel needed to by reduced by a few MM so i just shoe shined it with an emery cloth.

[draconianruler]

I agree with Rocco, Freezing and heating your parts is unnecessary. Just go get some molygraph or other high pressure lube. A pair of 20 dollar Harbor frieght digital calipers are nice to make sure your parts will have the correct press fit. Here's an E german build I did recently on a virgin Romy barrel. After measuring, the gas block area on the barrel needed to by reduced by a few MM so i just shoe shined it with an emery cloth.

Do you have to remove the barrel to install the front trunion or do you just use the barrel as the backing to rivet it in?

[nicoroshi]

Do you have to remove the barrel to install the front trunion or do you just use the barrel as the backing to rivet it in?

Removing the barrel from the trunnion before riveting is the correct way.
I believe 4thSBCT was only creating a head spaced front end at this point for later bending a flat, and attaching trunnions to (after he presses the barrel back out).
This way he has just created (for all intensive purposes) a matched, head spaced front end. May as well be number matching at that point.

[SJgunguy24]

Removing the barrel from the trunnion before riveting is the correct way.
I believe 4thSBCT was only creating a head spaced front end at this point for later bending a flat, and attaching trunnions to (after he presses the barrel back out).
This way he has just created (for all intensive purposes) a matched, head spaced front end. May as well be number matching at that point.

This is the best method I've come up with to build a virgin or non matching barrel. Do the machine work and headspace before that trunnion ever touches a receiver. It cuts the risk of damaging the receiver down quite a bit. If your building on a flat you need extra care so that soft piece of sheetmetal stays in the shape of a receiver.