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Old 11-17-2019, 10:10 AM
CatBacker88 CatBacker88 is offline
 
Join Date: Jul 2019
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Default Rebuilt M1 with Problematic Zero

I have a former Blue Sky rifle that was rebuilt for me by Don McCoy (https://www.legacy.com/obituaries/na...3897959&page=2) in 1995. The original barrel was totally shot out, so along with all the other repairs Mac installed a Citadel barrel, chambered in .308. I never had time to do much more than function check the finished product, but while doing so I attempted to zero the rifle as well, and while it grouped well, i had to run the rear site nearly to the left end of the adjustment scale for a 50 yard zero. The rifle otherwise functioned perfectly, so I was hesitant to go back to a legendary master armorer to complain. Lots of life has gone by since then and now I'd like to shoot this thing again and the problem is still there. Is it likely that new barrel just isn't indexed properly? Could it be something else causing this? Any suggestions would sure be appreciated!
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Old 11-17-2019, 10:16 AM
bigwagon bigwagon is offline
 
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Location: Milwaukee, WI
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Have you checked the front sight alignment on the gas cylinder?
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Old 11-17-2019, 10:49 AM
la Fiere la Fiere is offline
 
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Location: Northern California - SF peninsula
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Quote:
Originally Posted by bigwagon View Post
Have you checked the front sight alignment on the gas cylinder?

This is the most likely problem. Move the front sight 8 thousandths for each MOA of adjustment. Be sure to tighten the set screw well when you're done.
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  #4  
Old 11-17-2019, 11:54 AM
ceresco ceresco is offline
 
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The human eye is capable of detecting small angular deviations. Set the rifle up and look at the front sight. Re-indexing the barrel is a simple job for anyone with the tools. If the rifle shoots way off with the sights centered, re-indexing is the best solution. Moving the front sight on the base is OK for small adjustments. Good Shooting. ..
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  #5  
Old 11-17-2019, 03:40 PM
Gewehr43 Gewehr43 is offline
 
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I would certainly check the sight alignment as others have suggested.
BTW......I adjust the front sight in it's dovetail to zero it. Is there some reason you cant do that? Though I realize from your description it MIGHT be excessive.

Also since the rifle is match conditioned re-indexing (rotating the barrel slightly) it could be done but would be major work. The handguards etc would need to be broken free to then allow the vice to lock onto the barreled action...…

Check where the front sight is on the dove tail before you go crazy with this......
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Old 11-17-2019, 08:43 PM
lapriester lapriester is offline
 
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Location: Cobb, N California
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I don't want to fault anyone but, if lots of McCoy rifles need the front sight moved all the way right or left on the gas cylinder to attain proper zero then insufficient care was taken during the indexing process on too many rifles. Though the wide base cylinder was created to compensate for index variences due to the crude technology used in the 40's to index, en mass, thousands of rifles and minimize rejects, far better technology is cheaply available today to simplify almost perfect indexing. It's not rocket science to get it done precisely. Caveman methods like two long rods and eyeballing should be considered extinct these days. Even a $7 Harbor Freight angle finder can do better.

Also, my experience tells me that to use a gas cylinder other than the one intended to be used on the finished rifle, to do the indexing, can lead to less than acceptable results. I used to use a new, tight cylinder to do my indexing and found, on 3 of 20 jobs, that index was unacceptably off when the cylinder to be used was installed.
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  #7  
Old 11-18-2019, 04:57 PM
CatBacker88 CatBacker88 is offline
 
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I thank everyone for the recommendations. I actually did move the front sight when I first tried to zero, enough to make me suspect the barrel is just not indexed properly. Mr. Lapriester mentioned use of two long rods and eyeballing, and as a matter of fact that's what Don used. I'd been referred to him by a friend from the South Bay Rod and Gun Club as a good guy to see about re-barreling my clunker. I had no idea he was a (retired) legend among Navy rifle teams! I just called him up and he said come on over, he was between jobs. He had a nice shop in his garage, made me deeply jealous. He had a selection of barrels, all new, ranging from very basic to the very best. Also had coffee cans and bins and drawers of parts on hand. He mentioned a year or two earlier he'd purchased 300 (yes, 300) rifles from some outfit I recognized at the time but can't recall and had spent a ton of time breaking them all down for parts. He had all sorts of gauges and fixtures to sort out the good, bad and ugly, said he trashed the trash, sold the wood to somebody I forget, and had been using all those receivers and some of the parts to build match guns, none of which I could afford. Anyway, he detail stripped my rifle, pronounced the barrel a tomato stake (which I already knew) and methodically evaluated every single part and replaced any that didn't suit him, explaining in GREAT detail along the way what he was looking for and how he selected the specific part to use. He even had a setup for gauging and re-bending my op rod to spec. Just the nicest and cordial guy you would ever want to talk guns with. I was absolutely mesmerized. Charged me $300 and that included several replacement parts, new gas cylinder, a ham sandwich and a beer. Great memory. I guess I'll go get that barrel indexed now!
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Old 11-18-2019, 06:28 PM
Gewehr43 Gewehr43 is offline
 
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I too had the pleasure of meeting him several times over the years..... Great guy!

FWIW...… Unless the front sight is overhanging the dovetail on one side or the other, I don't worry about it...… just shoot the thing.
So the reverse being true..... unless I had a chamber issue or something, I wouldn't bother trying to index the rifle closer.

I understand that cosmetically it might bother you but if the rifle shoots, don't fix something that isn't broke...……….
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Old 11-18-2019, 10:53 PM
lapriester lapriester is offline
 
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Oh, and BTW, the barrel sounds like it's under indexed. That can actually happen if it took a really tight crush to index the barrel. When I've installed some very tight barrels I've found, for some odd reason, the next morning an index recheck found it underindexed. I've observed that several times. Perhaps that is the case here.
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  #10  
Old 11-19-2019, 03:08 PM
JimF JimF is offline
 
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Quote:
Originally Posted by lapriester View Post
Oh, and BTW, the barrel sounds like it's under indexed. That can actually happen if it took a really tight crush to index the barrel. When I've installed some very tight barrels I've found, for some odd reason, the next morning an index recheck found it underindexed. I've observed that several times. Perhaps that is the case here.
Larry . . . .

Are you saying the receiver backed-off a mite during the night . . . by ITSELF!!??
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