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Custom 30-06 wont chamber LC M72 ammo. What about the M70 rifles?

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  • Custom 30-06 wont chamber LC M72 ammo. What about the M70 rifles?

    Got a new custom rifle last week. Its a M24 spin-off in 30-06. Chambered with a standard reamer. It wont chamber a M72 round.

    Cartridge length is 3.332", which is under the SAAMI max length. I tried some reloads with a 175gr SMK, and it chambers without any issues. We can see the marks where it jammed in the lands. I had to smack the bolt hard to unjam it.

    Reply from a contact at Lake City:

    David,

    The shape of the ogive is extended forward farther than most factory ammo. Even the though the C.O.L may be under that of SAAMI the length to the taper of the ogive is extended on these loads.


    So what is it with those 173gr ogives?? How did the M70 rifles handled these rounds? Sounds like excessive freebore if a rifle cant throat a 3.332" 30-06 round! Its a shame really, I have a ton of that stuff....

    Was there a specific reamer used on the M70 sniper rifles? The 175gr SMK is definitely slimmer than the 173gr.










  • #2
    I have always set the OAL of my slow fire rounds off of the ogive for any bullet, due to the difference in each bullets shape. Run the M72 thru a seating die and set the bullets back a bit.

    Comment


    • #3
      Before I went and changed all my ammo, I would have a talk with your gunsmith about throating your chamber longer. Something along the lines of a 1-1.5 degree slope for 1/4". I know it sounds like fre‚Äčebore would be excessive, but it doesn't cause all that much inaccuracy. Take a look at match M16's. They have about 1/8" freebore and shoot "issued" ammo within 1moa. As long as everything starts nice and true in the throat it'll be allright shooting match ammo.

      Either way (leave or re-throat), I'd develop a plan to start reloading for these. It's the only way to get super accuracy.


      Comment


      • #4
        That's what my gunsmith told me. Re-chamber.

        I always reload, but I thought I'd give the M72 a try.

        That gun is a hammer with the 155gr PALMA. Although the Palma guys love to have it close to the lands, that bullet is not sensitive to large jump to the lands. Very tame recoil, awesome bullet.

        Comment


        • steveu
          steveu commented
          Editing a comment
          so, what did you do???

      • #5
        FWIW I don't have any issue with it in my 54 Winchester, send the M72 to me

        Comment


        • #6
          MescaBug, what did you end up doing with your chamber/ammo issue?
          I have a Winchester Model 70 USMC clone being built and sent in some M72 ammo for the test fire and it will not chamber... looking for some ideas as to my best course of action.
          Thanks,
          DW

          Comment


          • #7
            DW,

            I apologize for the late reply. I havent been around for a while.

            I never figure out what the problem was. The barreled action is still in my safe, unfired since 2015, lolll.

            Comment


            • deltawiskey
              deltawiskey commented
              Editing a comment
              No worries MescaBug, thanks for getting back to me!
              Dang... that's a sweet looking rifle to leave unfired for so long!
              I'm going to try and shorten the ammo just a little and see if it will work.
              DW

          • #8
            I have a plan for that rifle. Last time I tried the LC ammo, I didnt want to force rounds thru the chamber, and get them stuck.

            The problem is with the ogive. The taper starts further towards the tip. If you push the bullet too deep in the case, it will chamber but you'll end up with too much freebore. And you might have some overpressure problems.

            I guess they had a specific reamer when LC was used in the Winchester's 70.

            Comment


            • deltawiskey
              deltawiskey commented
              Editing a comment
              Yeah, I'm a little concerned about those issues...but I have a can full of M72 I'd like to shoot.
              Maybe I will have to buy another rifle so I can use the ammo : )
              Sure like that rifle of yours!!
              DW
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