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Posted: 3/16/2006 6:13:36 AM EDT
My 3rd build is being a bastard with the barrel. My problem is that I can't keep my receiver/trunion sturdy when i'm pressing it on. Anyone have any good methods for keeping the assembly straight and sturdy while under pressure?
Link Posted: 3/16/2006 10:04:46 AM EDT
After building 12 rifles (8 of my own and helping others with their's) the only way I will do a barrel installation is by doing the frozen/cold barrel into a hot trunion. At the last "build party" at my house, we all thought we would give it a try with fellow ARFCOM'er Pedro66's build and sure enough.. it literally slipped right in. No tension on the receiver, just a smooth slip fit.

We did use the press to aline the barrel pin exactly but I am sure we could have just used a rubber mallet just as easy. The barrel dropped in about 3/4 of the way with NO pushing whatsover.

thanks,
Ron
Link Posted: 3/16/2006 10:12:51 AM EDT
I've read about this. However, I don't have access to dry ice. :(
Link Posted: 3/16/2006 10:19:50 AM EDT
Soak it in ice water... we didn't have dry ice either.

thanks,
Ron
Link Posted: 3/16/2006 10:33:17 AM EDT
I've done a few by putting the barrel in the freezer and using a mapp gas torch to heat the trunnion. It slid in no problem, but it works better if the barrel is clean and has no burrs on it. Also, I've had a couple I didn't heatup enough and they wouldn't go. Tried again heating it longer and pushed in no problem.
Link Posted: 3/16/2006 11:32:21 AM EDT
excellent excellent! I will try it
Link Posted: 3/16/2006 11:40:25 AM EDT
one more questions, how hot should i get the trunion?

thanks guys
Link Posted: 3/16/2006 12:06:41 PM EDT
get the trunnion 250-300 degrees. Take your finger, stick it in your mouth to get some spit on it and slap the trunnion with it. If it goes PSSSTTTT..... its warm enough. Do not overheat it.
Link Posted: 3/16/2006 2:24:55 PM EDT

Originally Posted By schmalts:
get the trunnion 250-300 degrees. Take your finger, stick it in your mouth to get some spit on it and slap the trunnion with it. If it goes PSSSTTTT..... its warm enough. Do not overheat it.





thanks,
Ron
Link Posted: 3/16/2006 2:27:19 PM EDT

Originally Posted By turbosc20:
one more questions, how hot should i get the trunion?

thanks guys



Seriously..... when you see smoke coming off it from the oil and cosmolene residue, you know you are getting close. You will feel the radiant heat.

thanks,
Ron
Link Posted: 3/16/2006 6:07:39 PM EDT
omg it worked it worked!!!
http://phpix.planetb.net/cache/guns/romy%20ak47/DSC00249__scaled_640.jpg
I threw it [barrel] in the freezer for an hour, took the mapp torch to the trunion and then put the barrel that far into the trunion by hand! That was awesome. Thank you guys
Link Posted: 3/16/2006 6:12:30 PM EDT

Originally Posted By turbosc20:
That was awesome. Thank you guys








thanks,
Ron
Link Posted: 3/16/2006 6:38:31 PM EDT
Nice job
Link Posted: 3/16/2006 7:35:02 PM EDT
Dumb question....
Besides heating trunion/cooling barrel, what other method are you using? That is, are you using your press to push it in, or a threaded rod setup? I have this image of you just holding the trunion in one hand, the barrel in the other, and pushing them together!!
Link Posted: 3/17/2006 2:09:55 AM EDT

Originally Posted By rickomatic:
Dumb question....
Besides heating trunion/cooling barrel, what other method are you using? That is, are you using your press to push it in, or a threaded rod setup? I have this image of you just holding the trunion in one hand, the barrel in the other, and pushing them together!! hr


That's exactly what happened.
Link Posted: 3/19/2006 10:29:07 AM EDT
well ill say how i did all mine so far, but someone will probally say im doing it wrong and thats ok, but first of all i take a can of wd40 and spray the end of barrel and inside the trunion, then I put the end of the barrel with the muzzle break pointing down into a railroad tie and take a hammer and tap the trunion enough to get the barrel in enoughso it don't fall out, then i go over to my press and block up the rear sight block and us the press on the trunion, of course i have to stop when i get close to the barrel coming through and then switch to something smaller to drive it on through. Since i always have to basically do this stuff by my self it works out good for me, where as if i pressed from the other end, some help might be useful for that. For me it all seems to go in pretty easy if you lube it up real good before hand. Thats my 2 cents.
Link Posted: 3/20/2006 12:13:44 PM EDT

Originally Posted By hotboy041582:
someone will probally say im doing it wrong and thats ok.



I think as long as it works, it gives others another way of building.
Good job...
Link Posted: 3/20/2006 12:21:32 PM EDT
I have some 1/2" thick sheet Teflon some guy at a plastics company gave me. I ripped it to 1 1/2" wide and cut it up to make a jig to hold my receiver in a press. I cut a piece to fit in the receiver so no weight was on the feed ramp and clamped the two outer halves around the receiver. The outer halves take the pressure off the shell by supporting the front trunnion. Worked fine.
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