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Reassembling an 86 Romy kit and I'm having a hell of a time getting the hole to line up when pressing in my barrel. The barrel is so tight that when I'm pressing it in, it jumps in about 1/8"+ increments. It will jump from about a 16th too short to about a 16th too far every time. When too short it will swallow a Nogo and when too long it will not take a go gage. All of my other builds have not had this problem. Any suggestions?
 

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You might try polishing the barrel with some fine emory paper and then relube/repress.
 

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So it must have been tight when removing during the demil, correct?

If Yes,

If you decide to remove it you could sand the journal with a strip of fine emery cloth. A shoeshine motion all around for about a minute or two will remove a thousandth. Can be easily monitored with calipers. After emery cloth I polish the journal with 600 grit paper to a smooth gloss. And assemble with a spray of lithium grease.

Place the barrel in the freezer for a couple of hours? really helps a lot.


If No,

Could the barrel be riding on the trunnion rivets? Did you check for clearance for the inside rivet heads?
 

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try putting the barrel in the freezer for a couple of hours, the when it is good and frosty, heat the trunion with a torch. this will shrink the bareel somewhat and expand the tunion and should make it easier to get together.
 

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bbl

You might also try pulling the bbl in with allthread. That is waht I did on all my builds. It seems to pull in smaller increments than a press.
 

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An alternative method to reduce the impact of the large steps, since you already have the barrel in the trunnion, is to place a feeler gauge between the rsb and the rear trunnion as you apply pressure. The feeler gauge will act as a stop reducing the amount of barrel movement into the trunnion. I would recommend starting a 1/16 out of alignment and placing about 0.004 feeler gauge in postion, apply pressure, remove pressure on barrel, attempt to remove feeler gauge(it will probably be pinched) and check headspace/barrel pin alignment.

This technique works best if you measure the gap prior to removing the barrel, then add a couple of thousandths to allow for the pinch and you will be right on. I do this everytime and it makes it so easy compared to guessing as the barrel moves into place.
 

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A bit of polishing and good grease and heating the trunnion with a heat gun all make it easier for me.
That makes it go in smooth so I dial it in well.
Do it with a room temp trunnion and the barrel goes in in fits and spurts and tends to overshoot the headspacing!
 

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ammoboy2 said:
An alternative method to reduce the impact of the large steps, since you already have the barrel in the trunnion, is to place a feeler gauge between the rsb and the rear trunnion as you apply pressure. The feeler gauge will act as a stop reducing the amount of barrel movement into the trunnion. I would recommend starting a 1/16 out of alignment and placing about 0.004 feeler gauge in postion, apply pressure, remove pressure on barrel, attempt to remove feeler gauge(it will probably be pinched) and check headspace/barrel pin alignment.

This technique works best if you measure the gap prior to removing the barrel, then add a couple of thousandths to allow for the pinch and you will be right on. I do this everytime and it makes it so easy compared to guessing as the barrel moves into place.
+1 here. Real life-saver on "hoppy" barrels.
 

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"I'm using RCBS Case Lube liberally on both parts"

Consider going to your local Auto parts store - get some anti-sieze. Cheap, and very effective.
 

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Try this:
with the barrel about 1/8" too far out, put the bolt carrier in, the piston should be in the gas port. Use the largest diameter allthread that will go smoothly into the barrel it should be long enough that about 2 inches extend past the muzzle and the back of the bolt carrier, the allthread should go through the bolt carrier. Put the appropriate sized bolts on the ends of the allthread, begin tightening the bolts on the allthread, you dont want to tighten it enough to pull the barrel it you just want to build tension like a guitar string. When it`s tight tap the muzzle end of the allthread onto a concrete floor-the barrel will go in slightly, tighten the bolts again and tap again-barrel goes in just a little bit more.....keep doing this in small increments till your barrel pin hole lines up perfectly. In the final stages when you are almost there you will just put a wee bit of torque on the bolts and give it just a light tap....you`ll get the feel of it. It has worked for me every time.
Bossman
 

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You dont need any allthread or fancy grease, just use feller gauges between the rear of the RSB and the front of the trunnion, keep getting smaller until it lines up perfectly :D

-Ryan
 

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I put all barrels in with regular gun oil (CLP etc). I usually coat both parts and lay the receiver with trunnion on the dash of the truck during the hottest part of the day and put the barrel in the freezer for about half an hour. I then grab the parts and press them together quickly. They just pop right in place with no hitches. There is enough expansion and contraction to make the fit a little looser. I have also put them in dry at room temperature too without problems.
 

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SIGthusiast said:
Reassembling an 86 Romy kit and I'm having a hell of a time getting the hole to line up when pressing in my barrel. The barrel is so tight that when I'm pressing it in, it jumps in about 1/8"+ increments. It will jump from about a 16th too short to about a 16th too far every time. When too short it will swallow a Nogo and when too long it will not take a go gage. All of my other builds have not had this problem. Any suggestions?
are you useing a press? a trick i was told about on another site was to get it close to the point where it is almost ready to move then take a hammer and gently hit the bottom of the press to jar it to move in a small amount it worked for me :smile: ......after i went back and forth trying to hit the mark :goof:
 

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Apply smaller amounts of pressure (prior to the jump) and smack the press plate with a hammer. It will help the barrel creep along. Try this after a little polishing.
 

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In the past I used Lithium Grease for pressing barrels but ran into it seeping back out when parkerizing and baking paint. The surface always seemed to seep the Lithium Grease back out.

In the future I will try CLP as mentioned above(CLP degreases very easy prior to parkerize). I also like the idea of raping the press plate with a hammer when the barrel is under pressure. Thanks for the new ideas. :wink:
 

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tangotag said:
I also like the idea of raping the press plate with a hammer when the barrel is under pressure. Thanks for the new ideas. :wink:

Dunno, personally I think raping the press plate is going a bit far. What did it do to you?

:lol:
 

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I guess the concept of raping my press may seem odd. :shock:
I could try rapping my press. :cool:
Others might think I am just giving the press a bunch of rhythmic spoken delivery of rhymes. :twisted:

How about I use a FBH instead. :razz:
 

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^
|

What he said. :)

No really. I've done this many, many times, and I've had the same problem you're having. Walt-Oxie1's advice is what I do, and I always expect to press in and press out my barrel several times each build. Sometimes I do it once, and it fits. Sometimes it takes me three tries. The feeler gauge idea I think is the best. Before you remove your barrel during demilling, use a feeler gauge to see the distance between your breech and the lug on your trunnion. When you press in your barrel put the feeler gauge between the lug and the breech and press away. The feeler gauge will prevent you from overshooting your mark.
 
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