Undersized OD on GM barrel

[Scota4570]

I was given a parts set.  I am not complaining.  Free stuff is good.   

The barrel is sloppy loose the barrel channel.  I  checked the stock with a 13/16" pistol barrel and it fits right.   I measured the GM barrel, it is 0.016" under 13/16".  This obviously the problem, the barrel is defective.  I will not spend time building the rifle as it will never be right.  The undersized barrel will be fine for a future scratch build.  I need another barrel to build this parts set.  Weird. 

I guess my question is how often do barrels get shipped significantly off the nominal size?  I would have never thought to question it until now.   

[Ky-Flinter]

Perhaps someone draw-filed the barrel?

-Ron

[Scota4570]

No, it is the factory ground surface. 

[rich pierce]

I’d squeeze the stock. Are we talking 0.008” on each side?  Get it wet, heat it, squeeze it till it sets. Easy on something so short.

[A.Merrill]

   Rich is right. One thing, when you wet the barrel channel also wet the ramrod groove.  Don't ask how i know this.. .   Al

[davec2]

I'd try the wetting bit first.  However, I had a guy bring me a preserve that just had a sloppy barrel channel...even a little worse than yours.  But the stock wood was beautiful.  He wanted to bed the barrel with AcraGlass.  I did it for him.  Came out perfect and it waterproofed the heck to go the barrel channel.  You could not tell it had been done unless you pulled the barrel out of the stock.  Just an option.

[G_T]

What I did once was ran a tiny razor saw through the ramrod channel between the thimbles. Titebond II closed up the joint. Then adjusted the inletting slightly as required, and sanded the ramrod groove back to the proper radius with a dowel and sandpaper. The saw blade was chosen based on how much I had to close the channel.

This was for a barrel which was a hair wider at the breech and muzzle, and narrower at the waist, than the existing inlet.

It is not ideal to have to make an adjustment, but I'm satisfied with how the "fix" vanished in this case. I'm not recommending you or anyone do this, just indicating it has been done. Saw very carefully and cleanly. Be VERY careful with glue as you don't want it to soak into the wood in a way which will cause finish issues.

Gerald

[Scota4570]

Thanks for the ideas. 

I guess I have little to loose in trying.  Just a soaking it may stress the underside of the stock and cause a crack.   The ramrod web could  be a pivot point. 

Has anyone tried steam?  It's a half stock.  I'm thinking of steaming the forend in a plastic pipe.   Install the barrel, wrap it with a bunch of surgical tubing, and let it sit a day.  I imagine I should plug the ramrod hole with a steel rod to prevent crushing?  I have seen footage of wheelwrights and furniture makers doing this.  They make it look easy.  How long should I  steam the forend? 

Rich's plan?  Details please, you sound confident.  How exactly to squeeze it? clamps and steel rails?  Get it hot?  How hot?  Heat gun? Or heat he barrel up and drop it in a a warm wet stock?   Will the surgical tubing wrap work out? 

[flehto]

Coat the bbl w/ Oxyoke 1000 Plus {kinda waxy} and soak the stock for 4 hrs, put the bbl in and tightly wrap w/ surgical tubing. Let sit for a week and the fit will be perfect. Worked for me. My surgical tubing is quite a long length and the loops were 1-1/2" apart......Fred

[rich pierce]

If it can be done cold like Fred says go with that. I use a slit bicycle inner tube to squeeze when there’s no heat involved. It really lays flat and you can pull it tight as you want.

I was thinking to use a heat gun and get it plenty hot. Not enough to scorch but too hot to hold. This takes 10 minutes of heating, moving the heat gun around. Then simply put the barrel on and clamp the whole business in a carpenters vise focusing the pressure on  the top edges of the inlet. Alain’s and angle iron could also work. Have a partner so one can move quickly and keep the heat gun busy while clamping. Open in an hour. Should be plenty tight.

While not trad, the Acraglas will work like a charm but you’d have to do it after the whole business is inlet; tang and underlug, else you’d never chisel through that stuff. It would be invisible. Not knowing any better and reading too many magazines I glass bedded my first longrifle barrel. It cannot be discerned with the barrel in the gun.

[Bob Roller]

More production,get it done and out the door.Return it to GM and tell them to find an accurate
micrometer and someone who can read it. .8125 IS 13/16 if memory serves me right.

Bob Roller

[Marcruger]

"Coat the bbl w/ Oxyoke 1000 Plus {kinda waxy} and soak the stock for 4 hrs, put the bbl in and tightly wrap w/ surgical tubing. Let sit for a week and the fit will be perfect. Worked for me. My surgical tubing is quite a long length and the loops were 1-1/2" apart......Fred"

If Fred says it can be done this way, I would sure try it.  God Bless,   Marc

[Scota4570]

More production,get it done and out the door.Return it to GM and tell them to find an accurate
micrometer and someone who can read it. .08125 IS 13/16 if memory serves me right.

Bob Roller

Wish I could.  The barrel was a gift.  I have no idea how how old it is.  I do not have a receipt. 

[Top Jaw]

Im thinking the soak and wrap (&maybe heat) should work with a swamped barrel too.  I have a channel cut for an A wt green mt that has a replacement Colerain in it.  It’s very close, but slightly loose.  Was gonna Acura glass, but think I’ll try this first. 

[Scota4570]

I got the stock good and wet with hot tap water.  I then heated the barrel until I got a little straw color.  I put on gloves  .  Then installed the barrel  and wrapped it the assembly in paper towels to prevent burning the surgical tubing.  Then wrapped tightly with about 10' of surgical tubing. 

It is very tight after 24 hours.