Garand Gas Ports and Cylinders

[smokeywolf]

Tore down my Garand; this one... http://castboolits.gunloads.com/show...-to-the-Family

Learned a couple of things. She hasn't been stripped, cleaned and re-greased in decades; could tell by the degree to which the grease has congealed. Also, the op rod catch had been modified to what is now commonly known as a Holbrook Device. Knowing my father, who redesigned everything on the rifle but the action. He almost certainly, back in the 1950s, also modded the op rod catch to prevent the en-bloc clips from being flung into the dirt or brush. Dad was almost obsessive about keeping dirt out of his firearms.

My question is, how tight a fit must the opening in the gas cylinder be to the hole (port) in the barrel? I would say there is .001 to .002 gap between the opening in the top of my gas cylinder and the port on the underside of the barrel. Is gas cylinder to barrel, particularly at the gas port, supposed to be a tight surface to surface fit?

[leebuilder]

Good Morning smokeywolf, i just glanced thru TM9-1275. I cant find any dimentional info, since it is gauged. But there should be some clearence there. My rifle has a least a .001 clearence.
Be safe.

[akajun]

None, in fact you want to peen the splines on top of the barrel to draw the gas cylinder up so seal that surface, and to stop wiggle as the gas cylinder is where the front sight attaches. Read up on National match modification of gas cylinders. Granted you dont need to bore out the back ring but make sure you have clearance between the back of the cylinder and the front handguard, make sure the gas cylinder is tight and does not wiggle. Another thing is to find a gas lock that "times" by hand to 5:30 or so when it bottoms out, then apply red loctite and torque it in place.

[smokeywolf]

None, in fact you want to peen the splines on top of the barrel to draw the gas cylinder up so seal that surface, and to stop wiggle as the gas cylinder is where the front sight attaches. Read up on National match modification of gas cylinders. Granted you dont need to bore out the back ring but make sure you have clearance between the back of the cylinder and the front handguard, make sure the gas cylinder is tight and does not wiggle. Another thing is to find a gas lock that "times" by hand to 5:30 or so when it bottoms out, then apply red loctite and torque it in place.

Thanks for that info akajun. I can see that I need to put a pic or two of my Garand in this thread, instead of just linking to a previous thread about it. I do know about peening the splines, which actually serve to lock the gas cylinder to the barrel radially, but does not actually draw the gas cylinder up against the barrel's gas port. In my case that's a moot point, as my barrel has not splines and the front sight is mounted directly to the barrel.

Here's a few pics so you know that, "this isn't your daddy's M1 Garand".


The gas cylinder is directly under the stainless bands. The port under the forward band.

[Hardcast416taylor]

BOY! Did you take me back showing that magazine cover of the M-1. I always wondered what ever happens to the guns that made the cover of the gun rags. You have told us about a very nice worked one. Thanks for the trip back in time.Robert

[akajun]

Actually if you peen the upper splines only it does draw the cylinder up, but no, you dont want to go peening on that gun, beautiful.
I would just leave it alone. Your not gonna be shooting that gun enough to worry about.

[smokeywolf]

Actually if you peen the upper splines only it does draw the cylinder up, but no, you dont want to go peening on that gun, beautiful.
I would just leave it alone. Your not gonna be shooting that gun enough to worry about.

Actually, it is my intention to manufacture and procure enough extra parts for the Garand to provide for the continued shooting pleasure of my descendants for generations to come. If I have my way, I'll likely shoot this barrel out before I go on to the happy hunting grounds. I have the knowledge, skills, machinery and tooling required to ensure that Grampa's Garand can keep shooting for another 200 years. Don't know if my descendants will have those skills, so it's up to me.