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Posted: 1/7/2012 12:54:04 PM EDT
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Alright gents,
About a year back I bought an M1 Garand that had been converted to .308, first mistake I know... It has an adjustable gas plug in it. Is the adjustable gas plug needed for .308? So I take it out to the range to fire and it won't cycle completely, eject or feed. I installed a new Op Rod spring and that has not fixed the problem. Additionally, the bolt and operating rod have a nasty tendency to come out of their track/alignment. Do I need a new bolt and/or op rod or is it another issue? |
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Not sure if this will help, but I have Schuster adjustable gas regulators on my M1, and M1A. I have them to cut down just a bit on the recoil impulse and the wear and tear of associated parts. When adjusted down too far, they will not allow enough gas to cycle the action, so if you haven't already, try adjusting the gas regulator open a bit more and see if that cures the issue. |
| A gas plug isnt going to help if the op rod is jumping its track, there may be something else going on with the rifle that you may or may not be able to internet address. I would seek the advice of a smith on this one to get right to the point and get a jist of the condition of the rifle and the conversion. I know the smiths around here only run about $35 an hour good luck. |
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IMHO....I'd start with........
Check gas port hole size and op rod tab dimentions. Also, check the op rod spring, I won't/don't usually replace with a "extra power spring". For me, the standard replacement spring is GTG. Aloha, Mark For starters............ Tip: Barrel Gas Port for .308 M1 Garand
From: Gus Fisher EMAIL: Date: 18 May 1999 Time: 11:07:33 Comments Most of the standard replacement .308 barrels seem to have a gas port hole size around .080", which is correct for .30-06, but NOT for .308. The issue 7.62mm barrel had a gas port size of .106." This hole size is actually larger than required. I find the Number Drill bit that will give you a .096" hole is plenty. Some people like .100", but I've never found that to be required as long as the ammo falls in spec with military ball or Federal American Eagle or Premium Ammo. I spend a LOT of time aligning the hole in the drill press to ensure the larger sized drill bit will go down through the center of the hole. It helps that the path of least resistance for the larger drill bit will pretty much keep it centered when you drill it. Any metal burrs, that result from the drilling, get smoothed out after 10 to 20 rounds. M1 Operating Rod and Spring Specifications
Piston Diameter: .5260 to .5253 (under .5250 calls for rejection) Piston Thickness: .190 to .155 Tab/Lug Height: .320 to .317 (under .310 calls for rejection) Tab/Lug Thickness: .100 to .095 Tab/Lug Width: .265 to .235 Spring Length: 19 to 20.25 inches * Operating rod spring must be right-hand wound and free of kinks or flat spots Posted By: Island hopper (CMP forum) |
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I have a .308 Garand that had function problems when I first got it. On mine it turned out to have the gas port drilled to .30-06 size. I opened it up to the issue size of .106 and that took care of the short stroking. I later added a Schuster adjustable gas plug to fine tune the stroke and it ended up giving me beter groups when shooting it as well. Check the gas port size first. If it is OK and yours has a Schuster plug, then open it up some. If it has a McCann gas plug you will need to install the larger size port inside the plug. Good luck. |
| I had a M1 Garand built for me by Tony Giacobbi out of New Jersey. He does excellent work. At first mine had the exact same problem yours did. The issue is with the gas port hole on the barrel. It is just a tiny bit to small, which is why it is doing what it is doing. If I remember correctly the hole size needs to be .41 (I think) ... and I got that info from Tony Giacobbe. I went to the hardware store and bought the proper size drill bit and re drilled the hole myself. Worked like a champ. Solved my issue right away. In fact it would sling the brass a good 5 yards away after that. As for having a .308 garand, I don't think there is anything wrong with it. When I had mine built, 7.62x51 was $150 for 1000 rounds and 30.06 was much more expensive.... now it's the other way around. Call Tony and ask his advice. his website is... www.garandguy.com |
| From Kulek's book on the M1 Garand. The gas port on the 308 M1 Garand should be .089". Which is a #43 drill bit. For a .106" hole, that would be a #36 drill bit. A 30-06 Garand has a .079" hole, which uses a #47 bit. If a #47 bit goes in, but a #43 does not, then the hole is too small. The hole should not be smaller than a #43, and not larger than a #36. |
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