Replacing M1 Gas Piston

[ARCHIVED THREAD] - Replacing M1 Gas Piston

Posted: 9/13/2010 4:50:34 PM EDT

The gas piston on my Garand is under the minimum diameter (min. is 0.5250", mine measures ~0.5170") and it's causing some cycling issues. I'm assuming replacing the piston head will help with this issue, but I'm not really sure if it's a DIY project or if I should send it in to a smith.

After searching the site and archives, I came across this:

"To remove the old piston the op rod is first placed in a vise that has protected
jaws. The straight sides of the op rod are against the jaw faces. A 5/16" steel rod
is inserted down the tube where the op rod spring is normally inserted. The op
rod is heated just behind the tip with a propane torch to a glow just below a red
glow.

Applying a couple of firm strikes to the end of the steel rod frees to old piston,
which pops off the end of the op rod tube. Once the op rod tube has air cooled the
inside of the tube end is deburred and cleaned. The op rod assembly, less the
piston, is then measured (tolerances of 17.170" -0.005")."

The new tip and rod are silver soldered or brazed together using an oxy-acetylene
torch. Overall length is 17.330" -0.010

I have access and experience with the proper tools, and it looks like SARCO carries piston heads.

Has anyone attempted this themselves, or is it best left to a smith that specializes in Garands?

Posted: 9/13/2010 5:02:37 PM EDT

[#1]

While you can do it, unless you're up on all the pitfalls, I'd let a good M1 'smith do it.
There are issues with brazing the stainless head on the carbon tube.

If you'd like to do it, invest a few bucks in the Jerry Kuhnhausen shop manual on the M1 and M14. This is a real gunsmiths shop manual that covers EVERYTHING about the rifles in considerable depth.
This is NOT the usual reprints of old GI manuals or short articles. This is the real deal written by a Master.
Among other things, it covers everything on accurizing, trigger work, and new piston head installation in detail. This is the best money an M1 or M1A owner can spend:

http://www.brownells.com/.aspx/pid=25718/Product/THE_U_S___30_CALIBER_GAS_OPERATED_SERVICE_RIFLES_A_SHOP_MANUAL

Posted: 9/14/2010 3:10:10 PM EDT

[#2]

IF you need a new piston installed at the end of the Op Rod, send it to Columbus Machine Works in Ohio. Mike Stacey took over for the previous owner who repaired/re-bent Op Rods. He does great work and a fast turn around time. Give him a call and speak to him.

Mike Stacey
Columbus Machine Works, Inc.
2491 Fairwood Avenue
Columbus, Ohio 43207
614.409.0244 begin_of_the_skype_highlighting 614.409.0244 end_of_the_skype_highlighting
614.409.0245 fax

[ARCHIVED THREAD] - Replacing M1 Gas Piston

Armory » M1 / M14 / M1 Carbine

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