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  1. #1

    Default Garand op rod damage

    Hello all,
    I read often that a hot load with the wrong pressure curve can bend or damage the op-rod on a Garand. I would like to know exactly where the op-rod bends when this happens. A picture of a bent op-rod would be great if someone has one. Also, is there a particular measurement or test to check for a slight bend if it's not visually apparent?
    TIA
    DaveL
    Last edited by DaveL; 11-19-2017 at 08:31.

  2. #2
    leftyo Guest

    Default

    honestly all the years ive heard this, i have never seen a bent op-rod. however there are many pictures out there of an M-1's heel being cracked!

  3. #3
    Join Date
    Sep 2009
    Location
    London, Ontario
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    3,251

    Default

    Never seen any rifle damaged by the ammo alone. Never seen an M1 Rifle damaged by the ammo either. I'm of the opinion that the whole idea is an internet myth/fairy tale. Never heard this story until there was an internet. There is no documented or lab tested case of an M1 op rod being damaged by the ammo alone. All evidence is strictly anecdotal. The "I knew a guy on a range one time..." or "There was a guy one time..." posts. The very mention of it starts huge arguments on the assorted forums(never seen it here though). So does my having fired a box of Winchester 220 grain Silvertips(The original ST. A jacketed SP bullet with an Al cap over the exposed lead. Fabulous bullet.) out of my M1 with no fuss. Shot a ground hog with one long ago. Took the bottom of the head clean off and the second shot(the thing was still moving.) blew the entire off side into mush.
    Considering that JC took a regular factory rifle, loaded ammo running from the regular Blue Pill of 75,000 PSI to 125,000 PSI before there was any damage(same rifle fired another 5,000 rounds of standard Ball ammo with no further damage too), the next story about it being "port pressure" isn't proven either. It follows that 75,000 PSI plus chamber pressure will also have higher "port pressure" too.
    M1 op rods must be bent to work. It's how they go around the receiver from the barrel.
    The end of the op rod(piston) and the gas tube itself can get worn to the point gasses blow around the op rod. There are gauges and actual measurements for that. Minimum diameter for the piston is .525". Max diameter for the gas tube is 0.532".
    Spelling and grammar count!

  4. #4

    Default

    Op rods can bend between the tube and charging handle if pressures too high. Lead edge of cam slot can chip off. Rod can dismount if the rail lug is worn and undersized. These things can happen.

  5. #5
    Join Date
    Sep 2009
    Location
    London, Ontario
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    3,251

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    "...if pressures too high..." There's no laboratory documentation of any M1 Rifle being damaged by the ammo alone. Only second or third hand anecdotal evidence. And that did not appear, anywhere, until the Internet came along.
    What is documented is JC himself testing the rifle with ammo he loaded that went up to 125,000 PSI. No damage to the op rod at all. At 125,000 PSI, the left locking lug cracked. The same rifle, with no repairs, fired another 5,000 rounds of service ammo with no further damage of any kind.
    There's also the one about how using a heavier than 180 grain bullet will cause damage. John R. Clarke wrote a reloading for the M1 article in the March 1986 issue of American Rifleman magazine. Wherein there is load data for 190 and 200 grain bullets. Nice Matchkings too.
    https://www.scribd.com/document/4085...Rifle-J-Clarke
    Spelling and grammar count!

  6. Default

    This site has some time-pressure curves and talks about the idea.

    garandgear.com
    Last edited by barretcreek; 11-22-2017 at 02:35.

  7. #7

    Default

    Thanks for the responses guys.
    barretcreek, that's a very interesting site. Definitely worth a look-see.

  8. #8

    Default

    Quote Originally Posted by Sunray View Post
    "...if pressures too high..." There's no laboratory documentation of any M1 Rifle being damaged by the ammo alone. Only second or third hand anecdotal evidence. And that did not appear, anywhere, until the Internet came along.
    What is documented is JC himself testing the rifle with ammo he loaded that went up to 125,000 PSI. No damage to the op rod at all. At 125,000 PSI, the left locking lug cracked. The same rifle, with no repairs, fired another 5,000 rounds of service ammo with no further damage of any kind.
    There's also the one about how using a heavier than 180 grain bullet will cause damage. John R. Clarke wrote a reloading for the M1 article in the March 1986 issue of American Rifleman magazine. Wherein there is load data for 190 and 200 grain bullets. Nice Matchkings too.
    https://www.scribd.com/document/4085...Rifle-J-Clarke
    And yet op rods become damaged, chipped, bent, etc. "Ammo alone". What does that mean? That they weren't stepped on? The evidence is clear--some types of ammo deliver higher doses of energy into the system, such that in real-world conditions, the probability of increased wear and eventual damage is increased. Shoot 200gr bullets with slow powder at 80,000 PSI to your heart's content. I'll sell you some replacement op rods--at a premium, obviously.
    Last edited by togor; 11-28-2017 at 07:11.

  9. #9
    Join Date
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    Location
    Georgia
    Posts
    3,693

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    [url]https://www.scribd.com/document/40852596/Reloading-for-the-M1-Rifle-J-Clarke[/url

    Thank you for this link! Sincerely. bruce.
    " Unlike most conservatives, libs have no problem exploiting dead children and dancing on their graves."

  10. Default

    There's always the adjustable gas plug option.

    I have hunted with an M1 using Remington CoreLokt 150's. Still goin'.

    PD

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