M1 Garand Op Rod fail

D

DarthNul

New member
I picked up a "CMP Special" M1 a couple of months ago. It's got a new match grade .308 barrel, new black walnut furniture and all other parts are either refurbished, refinished or new.

I was spending some time with it today before putting it away for the winter and after about 25 rounds, the bolt just stayed open after firing. The op rod didn't spring forward and the bolt didn't close. Once it was unloaded, the op rod would slide easily forward and backward with no spring tension either way.

I field stripped it when I got home and the little shiny piston thingy that's supposed to be attached to the forward end of the op rod was just rattling around in the gas cylinder. It dropped right out when I tilted the muzzle up. The spring was going all the way through and out the front of the op rod.

Can this be welded or brazed back on? I've heard about op rods bending an breaking from using too heavy or too hot ammo. I've got less than 150 rounds through the rifle and it's all been 150 or 155 grain projectiles over starting to mid-range loads. I kind of thought hot ammo would lead to bend and crack rather than this.

What do I need to do to get my new favorite rifle going again?
 
It can be, but tolerances must be held when doing it. It needs to be held in-line, and at the correct position, in a vise, and then welded. If you get it off, it will not work correctly. A qualified gunsmith would be able to do it, with experience in welding gun parts. There are several things, during fitting and welding, that has to be done to keep from warping it.
 
The rod head (piston) should be silver brazed (silver soldered) rather than welded. With silver solder, the tube won't be damaged and the piston can be removed if necessary.

Jim
 
If you got it from the CMP, I'd contact them. I wouldn't be surprised if they fixed you up with a replacement op rod.
 
I suspect if you call CMP,or e-mail them,they will take care of you.

Thisis not a rack grade,its a CMP Special,fully reconditioned by CMP.

That is,if they get the chance to take care of you before it gets "fixed"
 
My mistake,Orlando,you are right.My mind mixed up two threads.There is one in Rifles,semi auto about a "Garand that followed me home".That OP picked a Special up at Anniston.
 
Thanks for the replies!

I did buy direct from the CMP. I plan to use the M1 occasionally for my Tuesday night high power league run by my local CMP club.

I emailed CMP customer service a little while ago. I think it takes them a few days to get to "new" emails. I'll be looking into my options while I wait for their answer.
 
Some of the CMP Garands in 7.62 NATO have barrels from Springfield Armory in Springfield, MA. All the ones the USN Match Conditioning Unit in San Diego gro from them were air gauged and those smaller than .3079" groove diameter were set aside for match use; they were very accurate. They were enscribed with the last two digits read on the gauge; a "78" indicates a .3078" groove diameter. I doubt any of these "tight" barrels were ever put in standard CMP Garands. The ones I saw at the CMP meeting last year were marked in the "8X" range meaning they were all over .3080" groove diameter.
 
Bart,

The Criterion barrel business was started by Krieger (it has since spun off to someone who worked for Krieger, IIRC) with the idea of providing some match grade precision to a more economical barrel for those who couldn't afford Krieger's match barrels. The Criterion barrels are button rifled to save cost, but that is done slightly undersize, and the are then hand lapped, so they are uniform in the bore. The finish on the short chamber is high and it runs very true on the two copies I have. Where it is not a match to Krieger brand match grade barrels is it is standard weight, not heavy, and it is chrome-moly steel rather than stainless.
 
Unclenick, tried to get detailed info from Criterion's web site on their barrels, but it's down past their home page.

I'm curious as to what the difference is between their "match" label compared to others. Specifically, when the button rifled barrel's contoured and lapped. "Match" grade has a wide range of meanings. And I'm well aware of the issues button rifled barrels put in M1 and M14NM/M1A had.
 
I don't know how much truth there is between the several types of "cut-rifling", as it is all cut, even broaches. The only difference from conventional "single point" rifling is that you cut one groove at a time, however you can keep deepening the cut, whereas with button or broach, both similar, they are not adjustable, unless you change cutters, and they do all the grooves at once.

Experience shows that forged rifling, where the barrel is squeezed onto a carbide rifling form, under huge pressure, is one of the best. If barrel makers want to brag, than this process can take the cat birds seat.

Anyhow, one maker will say theirs is better over the other, and it all boils down to how well done the process was performed. Did they take their time to do it right, or was it a quick production piece?. How well done was the gun-drilling and reaming? How even was the rifling from groove to groove? How close to spec was it held? What type of internal finish was done to the bore and chamber? Each type of cut rifling is gauged by the same inspection process. Some brag that "they don't have dimensional change issues". If a cutter can't change dimension down a bore, and the chips are cleared, nothing can change in the bore, unless they let it heat up. That is nothing but sales gimmick talk. I have seen very accurate guns, with barrels made by several processes.
 
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Why are (hammer) forged rifling barrels not popular with people wanting and getting best accuracy with button or cut rifling if they're one of the best?

What is the gauging - inspection process for cut rifled barrels?
 
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Bart, I would say it is how the complete process is done. According to what has/is being taught, the cold working of the barrels has advantages, along with the finish of the bore. Anyhow, I think it has everything to do with the processing steps, than it does to which way it was rifled. Below is a quote from FN, and a link to the article on hammer forging. Note, that a different stainless has to be used, if forging barrels, because of work hardening. The stress relieving process is different too. Anyhow, the more carefully machined barrels should be the best, no matter the rifling method. For the small shop, though, they might not be able to afford a hammer forge, since they run something like $1/2 mil.

The bore gauging should be done with air gauges.

http://www.mahr.com/en-us/Products/Metrology/By-Mahr-Product-Group/Millimar/Gages-and-Systems/-Millimar-Air-Gages-Overview/Air-Gages-Description/

Hammer forging has been proven to be the most accurate method of barrel production, providing a longer useful barrel life and greater accuracy. However, while cold hammer forging takes about 90 seconds per barrel (plus a longer setup time), button rifling is a much quicker process at about 30 seconds per barrel.
Click to expand...

http://www.thetruthaboutguns.com/2013/08/foghorn/a-look-inside-fnms-south-carolina-barrel-shop/

Here is a reprint of an article in Precision Shooting Magazine's 1995 Precision Shooting Annual:

http://www.firearmsid.com/feature%20articles/rifledbarrelmanuf/barrelmanufacture.htm

The only flaw they mention for hammer forging, is the tougher stress relief, and the OD of the barrel's contour needing cleaned up. Of course, you get this with button rifling, in that it has to be stress relieved before the final turning. Of course, this article is 19 years old.
 
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