AK Barrel Loose Need Help

[bjbrokaw]

I just finished my first build and the barrel is loose and wobbles in the trunnion. It's so loose I can press it in by hand. It was tight when I pressed it out but it had a big groove in the barrel but still fit tight but after parkerizing it ate away where the groove was and now it doesn't fit tight. How can I fix this to make it safe? I was thinknig about putting JB-Weld in the trunnion and smoothing it inside to make a tighter fit. Would that work or am I totally screwed.

Btw I already searched and couldn't find any threads on the topic so sorry if this has been discussed before.

[PolishMike]

May be a stupid question but do you have the barrel pin in?

[jumbopanda]

I just finished my first build and the barrel is loose and wobbles in the trunnion. It's so loose I can press it in by hand. It was tight when I pressed it out but it had a big groove in the barrel but still fit tight but after parkerizing it ate away where the groove was and now it doesn't fit tight. How can I fix this to make it safe? I was thinknig about putting JB-Weld in the trunnion and smoothing it inside to make a tighter fit. Would that work or am I totally screwed.

Btw I already searched and couldn't find any threads on the topic so sorry if this has been discussed before.

Do not use JB-weld! If there is still some interference in the fit, you may be able to tighten it up by knurling the barrel, or giving it a few hundred pricks with a center punch.

[bjbrokaw]

yes it is even loose after putting in the barrel pin.

[bjbrokaw]

The barrel pin is even a bit loose because I left the front trunnion in the park bath too long... (bangs head into wall) the park really ate it up where the groove was scraped into it. I had to drill out the barrel pin and a tiny piece was left stuck in there that scratched the hell out of the barrel on the way out.

[jumbopanda]

It's supposed to be tight even without the barrel pin. How long did you leave it in the parkerizing tank?

[thedrickel]

The part that usually gets galled (above the chamber) isn't even involved in the final press fit . . . what did you really do to it? There's no way it could just be loose. How long did you leave it in the park tank?

[bjbrokaw]

About 50 minutes at 180 -190 degrees... It was just long enough to give the receiver a nice dark color but was overkill for the trunnion and barrel.

[jumbopanda]

50 minutes should be just about right. I've parkerized barrels and trunnions for that long and the fit actually got tighter.

[bjbrokaw]

It was a homemade park solution so I may have added to much phosphoric acid. The receiver and the other parks came out great though it just affected the front trunnion the most.

[weezil_boi]

That barrel should be so tight that it has to be pressed / pounded back in. The amount of deterioration that you describe should not have been caused by 50 mins in a park bath. Although yours may be crazy if a homebrew.

We normally let parts sit for 15 minutes. Did you try to polish the barrel or inside of the trunion?

My guess is that if you tried to rough up the barrel to make it tight... it will work for awhile, but over time may start o loosen up?

Id look into a more permanent way to build it up, maybe some type of weld or solder?

[valleyrat]

The trunnion could be cracked from removing the barrel and pin, not unheard of and would effect barrel fit. Cracks are difficult to locate too. You need to mic the barrel and trunnion and check the interference fit. If its out of spec you could try knurling the barrel for better fit, but if the pin also fits loose I suggest you demill and buy another trunnion.

Seriously, don't use JB weld. That should be common sense.

[Ford8N]

Wow, I've never heard of this problem.

[mason1800]

I figure the blasting is what ate up the metal. So if you Blasted the metal for a long time, and then dunked it in for 50min, that would loosen something up.

[FEDUPWBS]

That barrel should be so tight that it has to be pressed / pounded back in. The amount of deterioration that you describe should not have been caused by 50 mins in a park bath. Although yours may be crazy if a homebrew.

We normally let parts sit for 15 minutes. Did you try to polish the barrel or inside of the trunion?

My guess is that if you tried to rough up the barrel to make it tight... it will work for awhile, but over time may start o loosen up?

Id look into a more permanent way to build it up, maybe some type of weld or solder?

FAIL!!