NOB needs help! (long)

[railhead]

Back story goes like this.....
I'm a pretty fair garage gunsmith. I used to be a machinist and Tig welder in the aerospace industry as a younger man. About four years ago I inherited an CAI monkey built Cetme from my buddy when he passed. First thing I did was check the bolt gap which was bad. I bought +2 and +4 roller and a new locking piece and nothing worked. So off came the barrel for a repress. Then I found that the trunnion had a gap between it and the rails which was causing the bolt head to get peened on one side. Out came the trunnion.
So armed with lots of Internet knowledge, a brand new barrel, a new TIG welder and a new 12 ton press me and my lightened wallet went to work. Got the trunnion welded in alright and everything seemed OK. So far so good. I went to press in the barrel next. Press the barrel down to where I wanted it but need just a hair more. One more little push. It wouldn't move. Push a little harder and POW. The barrel shot down too much. Damn! Try again. Same thing. DAMN! Try a third time. Uh Oh. Galled the new barrel all to hell. Goodnight Irene. I stuck it in the closet.
So here we are three years later. I have a galled barrel as well as the original barrel. The galled one isn't a real tight fit anymore so I guess it's junk. The original had a drill mark on the barrel exterior just forward of the trunnion where the barrel tapers down. Looks like something CAI did. It's probably .020- .030 deep. It was the reason I went with a new barrel in the first place. Plus I never liked the idea of turning the barrel 180 degrees as I thought the original barrel pin slot would be a potential weak spot in the chamber. I guess I'm just paranoid because lots of people have done it and it seems to work Ok. I honestly DO NOT want to spend more money on this thing. So, should I use the old barrel, try to salvage the galled one, or sell it off to someone who knows what the hell they're doing?
PS.. I bought a G3 kit at the same time thinking I would build one of those too. That is definitely going on the market. Nothing like jumping the gun. It's not cheap being impulsive.

[RLDBUSER]

im in the market for g3 kit and barrel, pm sent

[drine]

Use the old barrel turned 180 degrees. No harm. BTW, I gauled a brand new barrel too! It went on gunbroker and sold right away WITH the info that it was gauled. Someone want to turn it down and use it on a different build, AK IIRC. When you get close next time, take it out of the press and get the old hammer out and set up some brass or copper shims on the breach face and tap it into place. I've heard the same for bumping it back a few .001's, not enough to gaul. If it gets to be too much of a pain, part it out! Sell it as a kit just as the G3 and use the money from both to buy a new one that you don't have to mess with. The CETME will be full of US parts that might get you a better price than a normal kit. Just a thought!

[jbruney]

I've got one that's turned 180 and it percolates just fine. You could also have set your barrel and gap before installing the trunnion. Keep the faith and take your time.

My cetme rifles were a pita after all of the ak's, but the outcome is very worth all of the trouble.

[lima]

All of my "brand new in wrapper" Spansih CETME barrels had factory barrel pin slots machined in the wrong spot by the factory. I think everyone was in the same boat with these and does the 180 degree turn.

When I pressed mine in, I got some very light galling but not too bad.

As for the galling, how loose is it? Are the outside dimesnions changed over the whole barrel in all dimensions or just a few low spots? Can you move it by hand? I think the barrel pin is what really keeps the barrel in.

I used wooden blocks and some kisses with a plastic coated HF dead blow mallet to tap it to the correct gap spacing. I found the press would not give the the accuracy and would jump durring the final gap adjustments.

Curious, were you pressing the barrel from the front or the rear (inside receiver) of the trunion?

[Smokehouse69]

I pressed my barrel into a bare trunnion, I too had to flip my new Santa Barbara barrel because of the wrong groove location.
I used a copper/brass 3/8" bolt used for large electrical connections inserted into the chamber with two copper washers as backup. Then I used a 3 jaw puller to push the barrel into the trunnion. I greased up the trunion and barrel with copper Neverseize and started cranking the puller. It went in slick as a whistle. The first time I pushed it in to where I estimated the barrel should end up. I pushed it in too far and had a .003 bolt gap. Took a black Sharpie and drew a line around where the barrel was poking out of the trunnion, pushed it on the rest of the way out.
I had a very small amount of galling where the barrel pushed across the hole for the pin in the trunnion. I smoothed this area out inside the trunnion and polished the barrel where the galling was, lubed it up again and pushed it again. This time I pushed until I saw the very leading edge of the black mark coming out of the trunnion and stopped. Pulled off the gear puller and checked the bolt gap, I had .017. I tried to bump the barrel back another couple of thousandths, but I didn't have any success.
I drilled for the pin and drove the pin in, checked my gap and it had closed up to about .015. By the time I got the trunnion welded into the receiver and had cycled it a couple hundred times, it has closed up to a loose .012 and a tight .013.
I'll check it again when I've fired another 100 rounds through it, if it has closed appreciably more I'll put in some +2 or +4 rollers and check it.

[86thecat]

I've had good luck pulling the barrel into place before the trunnion is installed using an adapter on the barrel threads and a tube spacer. If you use a good lube on the barrel and a fine thread grade 7 threaded rod you can check the gap as you move the barrel and there is no jerking. What's the ratio- around 5 to 1? The gap closes 5 thou for every thou the barrel is moved?

[Hoover 1]

I've had good luck pulling the barrel into place before the trunnion is installed using an adapter on the barrel threads and a tube spacer. If you use a good lube on the barrel and a fine thread grade 7 threaded rod you can check the gap as you move the barrel and there is no jerking. What's the ratio- around 5 to 1? The gap closes 5 thou for every thou the barrel is moved?

Interesting!

Do you have a photo of you set up that you can post?

Thanks,

Hoover

[86thecat]

Here's the old thread.
http://www.militaryfirearm.com/Forum/showthread.php?t=1425
I've done a few this way with good results. Just be sure to use a good anti seize inside the trunnion and on the threaded rod as there is quite a bit of load when pulling the barrel in. Don't forget to check the inside of trunnion (where drilled) for burrs and roughness that will gall the barrel. Depending how the setup is held there can be torque on the barrel which will make it rotate a few degrees when pulled in, doesn't hurt anything but just FYI.