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So I have peened by barrel splines twice on my 1954 HRA Garand. I actually had to tap the cylinder back on with a rubber mallet so the fit was tight.

After shooting a couple of clips through it, it becomes a bit loose again. I figure it is the peening coming undone from the heat and recoil. I have followed the CMP instructions on how to peen along with some other articles on it.

Does anyone have a method that they use that is more effective? I'm thinking another alternative would be to shim the male ends of the gas cylinder splines with a light film of epoxy. I'd rather not do that.
 

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Take two ball bearings the size of a nickel and a vice. Ball 1 goes on one side of the gas cyl spline. Ball 2 goes on the other side of the gas cyl spline. Tighten vise to force ball bearings to slightly sqoosh the splines, making them bigger on each side. Don't over do it, you're just trying to displace a little metal, not force the hole bigger.
 

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I used a center-punch to dimple the splines on the top of the barrel - that pulls the window in the gas cylinder tighter against the port in the barrel.

Also, if there is only a slight amount of looseness, it may tighten itself after more firing due to gas fouling.

For cleaning, I don't remove the gas cylinder.

Jay Kosta
Endwell NY USA
 

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Might be your gas cylinder....try a different one.
 

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I have never had a gar cylinder loosen up that fast after peening,you must not be doing it correctly.
I use a flat punch starting approx 1/8 back from the front of splines. Tap each edge/side working my way to the back, repeat on each spline.
If you use a flat punch and slightly roll the edges it doesnt show and works well, never had one loosen up on me
 

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Discussion Starter #6
I used a socket to peen. If I use a punch should I hold the punch flat 90 degrees and strike? Or sort of cut at a 45 angle while striking?
 

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A socket willwork butyou really have to whack it hardto peen much as it lays on the whole length
I hold the punch at a angle, do one side at a time. Go slow and light, since you are only peening the width of the punch it doesnt take much. You can always go back if you need more.
Remember start the peening approx1/8 inch back from the front, that makes it easier to start the gas cylinder
 

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Socket not necessary to peen. The ball peen on the hammer is really all that is needed. Not necessary to hit it for all you're worth. Barrel steel is relatively soft and the material will move easily.
Jon
 

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If the splines are that worn and it's not in the gas cylinder, you'll chase that problem till you replace that barrel. Trust me I've been down that road more than once.
 

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So I have peened by barrel splines twice on my 1954 HRA Garand. I actually had to tap the cylinder back on with a rubber mallet so the fit was tight.

After shooting a couple of clips through it, it becomes a bit loose again. I figure it is the peening coming undone from the heat and recoil. I have followed the CMP instructions on how to peen along with some other articles on it.

Does anyone have a method that they use that is more effective? I'm thinking another alternative would be to shim the male ends of the gas cylinder splines with a light film of epoxy. I'd rather not do that.
Here is what you do so follow along, take your barreled action too the next gun show and find a Gas Cylinder Lock that starts too get firm at about the 5-5:30 position and doesn't turn past 6 o'clock with heavy thumb pressure. Your going too get some odd looks but its worth it trust me. When you find the one it buy it! And if at all possible use a high hump lock.

After you have peened the splines and have what you think is a good and driving fit, add some High Temp Lock Tite too the ways and splines NOT the G/C Lock Threads, then drive the G/C onto the barrel wipe off and extra lock tite that oozes out. Make sure the G/C Lock threads are still clean and now you can install the lock and plug.

When the G/C Lock is fitted/timed against the barrels Gas Cylinder Lock Stop Shoulder, it better supports the gas cylinder under recoil instead of depending on just the gas cylinder locking treads on the barrel alone.

And while we are on the subject of M1 gas cylinders, check the clearance of the rear ring too the handguard if its not clear meaning its touching the front part of the handguard file it square so it doesn't 1/8in clearance works wonders. Back too the ring on the gas cylinder again, if the ring touches the barrel it should only touch the barrel on its underside from about 4-8 o'clock, from 9-3 there should be no contact with the barrel. What this does is it doesn't allow the gas cylinder too whip/lever against the barrels ways/splines and gas cylinder lock treads under recoil.

In order too make your peening job last longer, don't pull the gas cylinder off every time you clean the rifle. Wipe off and clean everything you can reach, then dismount the G/C for a detail cleaning at the end of the season.
 

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I dealt with this before. The last time someone had cross threaded the gas lock onto the barrel threads, effectively striping them. They "looked" ok but we're not sharp , just rounded, and the pressure of firing would allow them to skip. The remedy is a barrel replacement and new gas lock.
 

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If the splines are properly peened no loctite or shims, etc is needed. Making it alot harder than it really is
 

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For cleaning, I don't remove the gas cylinder.

Jay Kosta
Endwell NY USA
Me, too. I don't see why it needs to come off, so I peened mine about 7 years ago and it's still tight. A few hundred rounds later.
 

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Not to mention that as the rifle is fired there will be a carbon build up over time. The carbon will also help to keep things from moving around.
Jon
 
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