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308 M1 Garand gas plug
- Thread starter Deles136
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Swampy
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Deles,
Same as for any cartridge.....
Start with the LARGEST opening and shoot single rounds. Enlarge the opening until the bolt begins to lock open after the brass is ejected. Then try to shoot multiple rounds from a clip. If you have reliable function from the clip, then you are there. If you are still getting short strokes, then enlarge again until the short strokes stop.
Best regards,
Swampy
Garands forever
Same as for any cartridge.....
Start with the LARGEST opening and shoot single rounds. Enlarge the opening until the bolt begins to lock open after the brass is ejected. Then try to shoot multiple rounds from a clip. If you have reliable function from the clip, then you are there. If you are still getting short strokes, then enlarge again until the short strokes stop.
Best regards,
Swampy
Garands forever
Swampy - Thanks but is the first size supposed to say LARGEST? Are you telling me to back the screw all the way out and then screw it in until I get where I should be? The setup on the M1 Garand I bought has two screws, one on top of the other and the lower screw is the adjustment and the upper(with the rifle standing on the butt of the stock) screw is for locking the two together.
Many thanks,
Many thanks,
Swampy
Member
Deles,
YES, the LARGEST is what you start with.
Think it through.... If you start with small openings and work to the larger openings you are SLAMMING the action with the maximum amount of gas pressure right at the beginning.
The whole point of using the gas ports to begin with is to prevent this very thing. You adjust from too little pressure (Large opening) till you reach the minimum pressure needed to get reliable function.
Swampy
Garands forever
YES, the LARGEST is what you start with.
Think it through.... If you start with small openings and work to the larger openings you are SLAMMING the action with the maximum amount of gas pressure right at the beginning.
The whole point of using the gas ports to begin with is to prevent this very thing. You adjust from too little pressure (Large opening) till you reach the minimum pressure needed to get reliable function.
Swampy
Garands forever
Swampy:
For those of us not in the know about the adjustable gas thingys (like ME!), is it set up so that if you are on the largest setting, that setting vents off the most gas, where as the samllest setting sends more gas to the operating assembly?
For those of us not in the know about the adjustable gas thingys (like ME!), is it set up so that if you are on the largest setting, that setting vents off the most gas, where as the samllest setting sends more gas to the operating assembly?
This is where I am reversed in my thinking. The device that is installed on my rifle restricts the amount of gas coming from the port in the barrel (I think). I now see that I will have to screw down, away from the muzzle, on the adjusting screw and back off until I allow just enough gas to pass through the gas port in the barrel to operate the action. OR am I reversed?
I tried sticking my 70 year old finger into a light socket to align the few remaining cells in my brain but I don't think I am sure yet.
Many thanks,
I tried sticking my 70 year old finger into a light socket to align the few remaining cells in my brain but I don't think I am sure yet.
Many thanks,
Swampy
Member
Deles,
What you are envisioning is not something that can be done with just a gas lock screw system. The op-rod would have to be modified and the gas cylinder as well.
Most of the adjustable gas port lock screws have an adjustable hole that VENTS gas from inside the gas cylinder to the outside, thereby REDUCING the pressure to the op-rod piston. They do not restrict the port in the barrel to cut the flow of pressure INTO the cylinder.
Best regards,
Swampy
Garands forever
What you are envisioning is not something that can be done with just a gas lock screw system. The op-rod would have to be modified and the gas cylinder as well.
Most of the adjustable gas port lock screws have an adjustable hole that VENTS gas from inside the gas cylinder to the outside, thereby REDUCING the pressure to the op-rod piston. They do not restrict the port in the barrel to cut the flow of pressure INTO the cylinder.
Best regards,
Swampy
Garands forever
Swampy - The device on my rifle is an after-market thingy and I will take it apart and see if I can tell how it vents the gas. I now get what you are saying and fully understand. The original screw on my rifle has been replaced with a hex head screw that is drilled and tapped down through the center and has two stubby set screws inside. I will see where the gas port is in ralation to the set screws and look for vent holes. I will get back later.
Many thanks,
Many thanks,
NOW ???? - The hollow bolt that replaces the screw that is directly above the op rod, all of this with the muzzle pointing up, has no vents nor do the two set screws inside of the hollow bolt. The end of the op rod is about even with the gas port in the barrel with the bolt closed. This hollow bolt forms an adjustable volume chamber just above the top/end of the op rod. I guess that I start with the least amount of volume of gas acting on the end of the op rod and slowly increase the volume until it cycles properly. The theory must be that if there is only a small space for the gas to force itself into then the pressure can be controlled by adjusting the volume of this small chamber. Or else I don't have a clue which is possible.
Many thanks,
Many thanks,
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