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Author Topic: G/M barrels any runout?  (Read 8055 times)

Offline Roger Fisher

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G/M barrels any runout?
« on: November 01, 2010, 04:33:30 PM »
Dragged a green mt barrel outta the basement rafters and its been there 15 years or so.  Is it a must to breech her with the emblem and cal stamping on bottom flat due to run out?  This is the first g/m I've used (I think) She is a 50 in 15/16th straight.  Plug is now shouldered up against the bore and tang tight with top flat; but I'm one flat away from having that stamping on the top.  I'm thinking to worry her in that one more flat and then draw file that fairly shallow stamping off? Or do I go all the way around (draw filing) so said stamping is on the bottom.  Looks as though I would still have a hair more than 1/2 inch plug depth.....

What do you Green Mt barrel experts have to say on this one? ::)
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Offline Ben I. Voss

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Re: G/M barrels any runout?
« Reply #1 on: November 01, 2010, 04:51:48 PM »
Roger, I'm no expert, but Green Mountain barrels are made in such a way that there should be no run-out. I've never had a problem with run-out on a GM barrel and I don't think you'll need to worry about it either - I'd finish her down where you have it indexed now.   Ben
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Offline P.W.Berkuta

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Re: G/M barrels any runout?
« Reply #2 on: November 01, 2010, 05:15:54 PM »
I use a lot of the GM barrels and I like them - for the price they are hard to beat. That said I still either mount their logo either on top or bottom. Some people don't mind if it shows and as you said you can file it off.
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FG1

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Re: G/M barrels any runout?
« Reply #3 on: November 01, 2010, 05:29:01 PM »
They have none. That are milled concentric with bore. ;)
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Offline LynnC

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Re: G/M barrels any runout?
« Reply #4 on: November 01, 2010, 06:38:43 PM »
I breeched one with GM logo one flat off top and it shoots center.  I think they are milled to center the bore and the logo placed on any flat.
BTW - I peened the logo and cal mark closed with a rounded punch, lightly drawfiled and browned.  Totally disapeared......Lynn
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billd

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Re: G/M barrels any runout?
« Reply #5 on: November 01, 2010, 07:16:49 PM »
Easiest way is to measure wall thickness.   Local machine shop, tech school, etc. if you don't have the tools. Then you know for sure.

Bill
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dannylj

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Re: G/M barrels any runout?
« Reply #6 on: November 01, 2010, 07:22:04 PM »
Roger, GM used to advertise that their barrels were drilled on center and there was no runout as in the old Douglas barrels. I have used a number of them with no problem. They are good shooting barrels.  Danny
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Offline smylee grouch

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Re: G/M barrels any runout?
« Reply #7 on: November 01, 2010, 07:35:26 PM »
Roger: Several years ago I bought two GM barrels from TOTW that were advertised as having runout at breech end,(1&1/8x42 in. long). Cut 10 inches off of breech end and rethreaded for breech, took out almost all runout so still breeched with runout on bottom. They shoot great.    Gary
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Offline bgf

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Re: G/M barrels any runout?
« Reply #8 on: November 01, 2010, 09:34:13 PM »
Roger,
Using a 15/16" GM .50 barrel, I just did the same thing for the first time ever (breeching a barrel) on the same barrel (but newer manufacturing).  Since it was my first time, I was intent on doing it "by the book" and put the logo on the bottom.  After a lot of filing and checking, I had almost exactly the prescribed minimum 1/2 inch of threads, by a hair.  Next time, having proved my point, I will live with it on top if that's close :).
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California Kid

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Re: G/M barrels any runout?
« Reply #9 on: November 01, 2010, 10:45:43 PM »
I've used a couple GM barrels with runout at the breech. muzzles were OK.
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Offline Don Getz

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Re: G/M barrels any runout?
« Reply #10 on: November 01, 2010, 11:20:35 PM »
Unless I am totally mistaken, I think Green Mtn. at one time did use some cold shaped octagon steel to make barrels, in
which case you might have a problem with run-out.   I have no idea if they still do this....I doubt it....nor do I know how
many they may have done that way.   I am talking about straight sided barrels,  you should not have a problem with any
of their swamped barrels............Don
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California Kid

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Re: G/M barrels any runout?
« Reply #11 on: November 01, 2010, 11:31:55 PM »
Don, these were straight barrels. I have no idea when they were made, but one was for a ladies gun I built in 2007.
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Offline D. Taylor Sapergia

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Re: G/M barrels any runout?
« Reply #12 on: November 02, 2010, 07:43:07 AM »
Back ion the 80's I worked for a man making muzzle loading rifles, and we ended up using a lot of GM barrels.  We watched them carefully for run-out, and made sure it was either at the top, or bottom.  Lots of their barrels, at that time, had run-out.
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northmn

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Re: G/M barrels any runout?
« Reply #13 on: November 02, 2010, 04:39:16 PM »
I do not know even if they would stamp the runout with a logo like Douglas did.  Old habits die hard and I still make my own breech plugs and place the run out at the bottom.  Also saves from filing off any logos.  Had a Douglas that had the Douglas at the bottom and still shot off.  thinking today long after it was sold that it may have been bent also.  13/16 45.

DP
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Offline Roger Fisher

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Re: G/M barrels any runout?
« Reply #14 on: November 02, 2010, 05:02:42 PM »
So seems as though I'll crank her around one more flat so that stamp in on top flat to insure any possible run out can be handled with vertical sight adjustment.  I'll then dress off that shallow stamping. w/o it being obvious ??? ::)

Thanks for the responses.   :)
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Offline Dphariss

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Re: G/M barrels any runout?
« Reply #15 on: November 02, 2010, 08:36:05 PM »
Quote from: Roger Fisher on November 01, 2010, 04:33:30 PM
Dragged a green mt barrel outta the basement rafters and its been there 15 years or so.  Is it a must to breech her with the emblem and cal stamping on bottom flat due to run out?  This is the first g/m I've used (I think) She is a 50 in 15/16th straight.  Plug is now shouldered up against the bore and tang tight with top flat; but I'm one flat away from having that stamping on the top.  I'm thinking to worry her in that one more flat and then draw file that fairly shallow stamping off? Or do I go all the way around (draw filing) so said stamping is on the bottom.  Looks as though I would still have a hair more than 1/2 inch plug depth.....

What do you Green Mt barrel experts have to say on this one? ::)

Put the touch mark down or up. Some of the ones from this time frame were not always centered at the breech.
I put the mark down regardless.
If you have a small polished ball peen or a small 3/16" or so diameter polished punch with some crown to the face peen the mark before filing it will disappear.
Dan
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Offline Pete G.

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Re: G/M barrels any runout?
« Reply #16 on: November 03, 2010, 01:56:32 AM »
For what it's worth.........I got a little too enthusiastic breeching a GM barrel and ended up with the maker's mark on the lower/left flat. With the sights centered it shot a little to the right (about 3" @ 25 yd). I got it centered with the front sight pushed a little to the right of center and the rear a little to the left. If I had it to do over I would probably just cut the notch in the rear sight a bit to the left.
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Offline Dale Halterman

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Re: G/M barrels any runout?
« Reply #17 on: November 04, 2010, 04:21:40 PM »
I did a Green Mountain barrel on a pistol a few years ago and had the logo off center - don't remember now exactly where it ended up- but rather than worry it around to the bottom, I just peened it over like Lynn said and finished it off with a little filing. The logo is stamped in and no metal is removed, so you just have to displace it back and you can eliminate a lot of filing.

Dale H
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northmn

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Re: G/M barrels any runout?
« Reply #18 on: November 04, 2010, 04:40:02 PM »
The problem with runout where its horizontal is that you can sight in at one range and it will be to one side closer and to another farther out.  I had a Douglas 45 that did that.  While it was not too bad, it is still a pain for target shooting.  That one had a little better than an inch at to both sides.  Runout needs to be vertical.

DP
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