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Discussion Starter · #1 ·
Picked up a project 1943 SA M1 Garand with a SA 6535448 11-64 Y63 PM barrel. The issue is the gas cylinder is an early D35449-1 model that has excessive play at the rear ring. The cylinder is loose and I know that I can tighten it by peening the threads on the barrel but I don't see how this will resolve the spacing and play between the rear ring and barrel. Should I replace the gas cylinder? At this point I'm not even sure that the gas cylinder would pass a gauge test. I haven't tried it yet. Thanks.

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First off don't peen the threads ,only the top spline sides at the land. Generally the lower two are left original .Unless they are heavily worn . By the looks of the rest of your rifle ,you might want to sell the early gas cylinder to a collector and just by as nice condition as you can find that gages good.
Wait to see how the newer one fits.
Have a feeling the early gas cylinder spline might have wear.
Only reason you want a tight fit is keep that front sight stationary . This was an enhancement that armorers did.
 

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Discussion Starter · #3 ·
First off don't peen the threads ,only the top spline sides at the land. Generally the lower two are left original .Unless they are heavily worn . By the looks of the rest of your rifle ,you might want to sell the early gas cylinder to a collector and just by as nice condition as you can find that gages good.
Wait to see how the newer one fits.
Have a feeling the early gas cylinder spline might have wear.
Only reason you want a tight fit is keep that front sight stationary . This was an enhancement that armorers did.
Sound advice. Leaning that way but wanted to make sure that I wasn't overlooking anything. Thanks.
 

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First off don't peen the threads ,only the top spline sides at the land. Generally the lower two are left original .Unless they are heavily worn . By the looks of the rest of your rifle ,you might want to sell the early gas cylinder to a collector and just by as nice condition as you can find that gages good.
Wait to see how the newer one fits.
Have a feeling the early gas cylinder spline might have wear.
Only reason you want a tight fit is keep that front sight stationary . This was an enhancement that armorers did.
I wouldn’t play with the barrel threads or splines to begin with, I would look online or talk to some collectors I know first. Then I would try to find at least two gas cylinders and if I had a set of plug gauges, I initially check the gas cylinder tube for correct dimensions and how it fit going on the barrel. I prefer my gas cylinders to fit as tight as possible.

Then check the gas cylinder lock to see what the timing is on the threads. I prefer the gas cylinder lock to start getting tight at about the 4-5 o’clock position requiring a gas cylinder wrench to bring it to the correct 6 o’clock position. I also check the poppet valve on the gas cylinder plug to make sure it functions properly.

Final check is the gas cylinder piston cylinder head. Check the dimensions and check for erosion wear. The reason I like the gas cylinder to have a tight fit is because I have a tool I made for removing tight fitting gas cylinders and because with a tight fitting gas cylinder you eliminate almost all gas leakage from the gas port thereby eliminating gas erosion damage to the threads and the spline.

Finally, I would take the stainless steel gas cylinder you currently have and sell it to a collector. There are a lot of collectors looking for an unpainted or unfinished stainless gas cylinder for an early Garand in their collection. As for the second gas cylinder I mentioned obtaining, if it gauges correctly and matches up with the rifles original manufacture date and manufacturer, I would put it on the side as a replacement or for future resale. Every Garand part I’ve ever seen has increased in value every year. Screws and pins that I use to purchase by the gross or bulk package now sell as single screws or pins for two or three times more than the original bulk cost.
 

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If the gas cylinder's play is only axial, i.e you can feel some movement fore and aft, but not any side ways, then you probably can leave it alone. My M1 has a bit of free play as I described, but has no problem holding zero and tight groups. BTW I'm shooting Berger 168 gr VLD Target bullets for best grouping.
 

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Discussion Starter · #8 ·
I wouldn’t play with the barrel threads or splines to begin with, I would look online or talk to some collectors I know first. Then I would try to find at least two gas cylinders and if I had a set of plug gauges, I initially check the gas cylinder tube for correct dimensions and how it fit going on the barrel. I prefer my gas cylinders to fit as tight as possible.

Then check the gas cylinder lock to see what the timing is on the threads. I prefer the gas cylinder lock to start getting tight at about the 4-5 o’clock position requiring a gas cylinder wrench to bring it to the correct 6 o’clock position. I also check the poppet valve on the gas cylinder plug to make sure it functions properly.

Final check is the gas cylinder piston cylinder head. Check the dimensions and check for erosion wear. The reason I like the gas cylinder to have a tight fit is because I have a tool I made for removing tight fitting gas cylinders and because with a tight fitting gas cylinder you eliminate almost all gas leakage from the gas port thereby eliminating gas erosion damage to the threads and the spline.

Finally, I would take the stainless steel gas cylinder you currently have and sell it to a collector. There are a lot of collectors looking for an unpainted or unfinished stainless gas cylinder for an early Garand in their collection. As for the second gas cylinder I mentioned obtaining, if it gauges correctly and matches up with the rifles original manufacture date and manufacturer, I would put it on the side as a replacement or for future resale. Every Garand part I’ve ever seen has increased in value every year. Screws and pins that I use to purchase by the gross or bulk package now sell as single screws or pins for two or three times more than the original bulk cost.
Great information. Thanks. Not too sue what I was thinking. Dug out my IHC from the safe and tried the gas cylinder off it. Fits nice and snug. No movement. Will be shopping for a appropriately dated gas cylinder. I checked the cylinder lock and screw and those too are not the appropriate models.
 

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Discussion Starter · #9 ·
If the gas cylinder's play is only axial, i.e you can feel some movement fore and aft, but not any side ways, then you probably can leave it alone. My M1 has a bit of free play as I described, but has no problem holding zero and tight groups. BTW I'm shooting Berger 168 gr VLD Target bullets for best grouping.
Unfortunately it moves sideways and up and down.
 

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The peening of splined started as a NM improvement ,most people wouldn't know the difference in accuracy.
Most gas cylinders on the M1 and M14 push on without tools ,some are sloppy.
As mentioned above rifle is a post war replacement barrel ,could be a rebuild marked .Which I probably leave alone , if not marked by one of the 60's era arsenal rebuilt facility. It could be anything from parts build to cmp replaced .
Lightly peened and tightened top spline wont hurt anything collector wise. If done properly you want be able to tell anyway.
 

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Discussion Starter · #11 ·
The peening of splined started as a NM improvement ,most people wouldn't know the difference in accuracy.
Most gas cylinders on the M1 and M14 push on without tools ,some are sloppy.
As mentioned above rifle is a post war replacement barrel ,could be a rebuild marked .Which I probably leave alone , if not marked by one of the 60's era arsenal rebuilt facility. It could be anything from parts build to cmp replaced .
Lightly peened and tightened top spline wont hurt anything collector wise. If done properly you want be able to tell anyway.
When I bought it the vendor had marked it as an arsenal rebuild. The stock had the Red River Arsenal stamp. Made sense with the '64 barrel but it was missing the handguards, buttplate and cylinder lock screw. When I got it and took it apart for cleaning I found that the receiver was missing any internal markings from the arsenal. The barrel was loose. When I hand tightened it the TDC aligned to the 2 o'clock position. I knew then it was someone's project gun. Had my gunsmith install the barrel. Lucked out with the stock. It was an IHC stock. Since my CMP IHC came with a hackberry stock I decided to use it on the IHC. Once I get the replacement cylinder it should be ready for the range.
 

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Peening the splines is the only rational solution, and an easy one. Gas cylinders must be firm or accuracy will be rotten. No g.c. should go on simply by tossing it on.

However, that part-numbered G.C. is worth a bunch of money on its own, even if it doesn't gauge very well.

It's from about Pearl Harbor time, maybe even a bit before, and even if it were somehow a match to the receiver, I'd NOT be using it. Too valuable to expose to shooting pressure and heat. They DO wear and wear out. Original finish on it would've been the very poor heat-resistant enamels of the time. NO, they won't take Parkerizing/phosphate. Decent late war and postwar g.c. units can be had for $100 or less.
 
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Incidentally, play at the REAR ring is a good thing, done to NM gas cylinders with boring tools to obviate differential pressure. When prepping accuracy and test rifles, I shot for .008" minimum clearance. But anywhere else, slop is BIG TROUBLE.
 

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Discussion Starter · #16 ·
Incidentally, play at the REAR ring is a good thing, done to NM gas cylinders with boring tools to obviate differential pressure. When prepping accuracy and test rifles, I shot for .008" minimum clearance. But anywhere else, slop is BIG TROUBLE.
Interesting to know because that was my main concern. The front had movement but nothing like the rear. Thanks
 
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