CMP Updates Ammo Specifications for 1903s, 1903a3 and M1 Garand

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  • wabbit

    Ultimate Member
    Apr 29, 2010
    5,207
    The gas system has nothing to do with peak chamber pressure and the gas tapped off at the gas port has nothing to do with blowing up a bolt, receiver, or barrel.

    The CMP is evidently not concerned about 03 actions handling pressure, because they just told everyone it can handle max pressure. If they were concerned, they would have picked a number below 50k CUP.

    I think QBeam was asking about bent op rods, which is not the warning CMP issued.
     

    ken792

    Ultimate Member
    Sep 2, 2011
    4,481
    Fairfax, VA
    I think QBeam was asking about bent op rods, which is not the warning CMP issued.

    Since he was talking about rifles blowing up and also mentioned 03s, it seemed like he was talking about chamber pressure, or at least got that mixed up with gas port pressure and dwell time.

    I have run across a lot of people who take the real or supposed gas port pressure issue to mean that the action itself is weak on the M1.
     

    Qbeam

    Ultimate Member
    Apr 16, 2008
    6,074
    Georgia
    I think QBeam was asking about bent op rods, which is not the warning CMP issued.

    It was a combination of both. They have said not to use heavy hunting loads for the M1 due to the OP rods, but I was thinking the CMP was doing an all encompassing message to cover all the scenarios, op rods and chambers. Evidently, I was wrong.

    Since he was talking about rifles blowing up and also mentioned 03s, it seemed like he was talking about chamber pressure, or at least got that mixed up with gas port pressure and dwell time.

    I have run across a lot of people who take the real or supposed gas port pressure issue to mean that the action itself is weak on the M1.

    I was thinking the CMP did a group message to cover all the scenarios op rod and chamber, with the M1 and 03/03A3.

    Q
     

    Doco Overboard

    Ultimate Member
    “Read This First”
    They come with the rifle inside the shipping case.
    I’d like to have an updated one for the o3’s
    I only have the old versions.
    Maybe they’ll print new ones up or provide an updated copy in the armorers section on the web page.
     

    JohnC

    Active Member
    May 29, 2019
    311
    Baltimore, MD
    “Read This First”
    They come with the rifle inside the shipping case.
    I’d like to have an updated one for the o3’s
    I only have the old versions.
    Maybe they’ll print new ones up or provide an updated copy in the armorers section on the web page.


    I'm more confused about greasing bullets- educate me?
     

    ken792

    Ultimate Member
    Sep 2, 2011
    4,481
    Fairfax, VA
    I'm more confused about greasing bullets- educate me?

    Excessive amounts of grease on the front of the bullets increased the amount of mass getting pushed down the bore. Grease on the chamber walls reduced brass adhesion under pressure and increased thrust imparted onto the bolt face.
     

    Doco Overboard

    Ultimate Member
    Excess grease between the neck and chamber When used by the old time shooters didn’t allow for correct release of bullet tension/ neck expansion which caused a massive increase in pressure.
    The tin can ammo created lumpy fouling and was thought to reduce velocity.
    Hatcher found cold welded bullets with about 300lbs of tension needed to pull them in some cases.
    In his note book, you could see a 03 barrel severely turned down in the strength test chapter right in front of the reinforce.
    I can’t remember if it finally took the 70 or upgraded 75 thou blue pill to make it come apart.
    Also in there ,a person could read about the Arisaka and then Garand copying it having the additional steel shroud that encircled the cartridge head Either in the face of the bolt or the barrel tenon on the Jap rifle.
    Nicks in the manufacturing discs used to form cartridge cases,how they are kept hard by manufacturing methods, imprinting a head stamp and all kinds of stuff.
    Evolution of 03 m1-2 ball ammo and so forth.
     

    Blacksmith101

    Grumpy Old Man
    Jun 22, 2012
    22,163
    Excess grease between the neck and chamber When used by the old time shooters didn’t allow for correct release of bullet tension/ neck expansion which caused a massive increase in pressure.
    The tin can ammo created lumpy fouling and was thought to reduce velocity.
    Hatcher found cold welded bullets with about 300lbs of tension needed to pull them in some cases.
    In his note book, you could see a 03 barrel severely turned down in the strength test chapter right in front of the reinforce.
    I can’t remember if it finally took the 70 or upgraded 75 thou blue pill to make it come apart.
    Also in there ,a person could read about the Arisaka and then Garand copying it having the additional steel shroud that encircled the cartridge head Either in the face of the bolt or the barrel tenon on the Jap rifle.
    Nicks in the manufacturing discs used to form cartridge cases,how they are kept hard by manufacturing methods, imprinting a head stamp and all kinds of stuff.
    Evolution of 03 m1-2 ball ammo and so forth.

    Lots of good stuff in Hatcher's Notebook everyone should read it especially if you own a Garand or 03. Here is a link to it on line in multiple formats including Kindle:
    https://archive.org/details/Hatchers_Notebook
     

    Ponder_MD

    Ultimate Member
    Mar 9, 2020
    4,565
    Maryland
    I have a lead on some reasonable commercial .30-06 ammo with a 150 grain bullet rated at 2910 fps muzzle velocity. I cannot find any specification on CUP pressure.

    Bottom line: is this cartridge safe for use with the Garand?
     

    ken792

    Ultimate Member
    Sep 2, 2011
    4,481
    Fairfax, VA
    I have a lead on some reasonable commercial .30-06 ammo with a 150 grain bullet rated at 2910 fps muzzle velocity. I cannot find any specification on CUP pressure.

    Bottom line: is this cartridge safe for use with the Garand?

    As long as it’s within SAAMI or CIP specs, its pressure is not going to exceed that CUP rating. CMP said max pressure CUP is fine.
     

    ken792

    Ultimate Member
    Sep 2, 2011
    4,481
    Fairfax, VA
    Isn’t it the gas port pressure you have to worry about


    Sent from my iPhone using Tapatalk

    Yes, but for the people who want to strictly follow the CMP recommendations, they made no mention of it. They simply said max chamber pressure is fine and set an arbitrary bullet weight.
     

    bigmancrisler

    2A Preacher
    Jun 4, 2020
    1,263
    Martinsburg, WV
    Yes, but for the people who want to strictly follow the CMP recommendations, they made no mention of it. They simply said max chamber pressure is fine and set an arbitrary bullet weight.


    Just to be safe I’m sticking with what is listed as garand safe loads (loaded up about 100 rounds for this weekend). Might look into getting the garand gear plug


    Sent from my iPhone using Tapatalk
     

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