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Changing the powder in short-cycling LC 68 M2-Ball

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    Changing the powder in short-cycling LC 68 M2-Ball

    Each round fires with no hesitation or hangfire. Recoil and muzzle blast seems similar with all the rounds. Some are ejected at about 1:00 o'clock as they should, some are ejected over my right shoulder (I'm in the sitting position). Those are probably giving the short cycles leaving an empty chamber. I'm thinking the primers are OK, the propellant might be the problem. I might pull a couple clips down and reassemble them with known good propellant. I can also look the dumped powder over for signs of deterioration. There were no signs of excess pressure. I've seen in a few places that powder can burn faster as it goes bad.
    I'll pull down two clips and reload with WW748 (which I have on hand). I'll report it here after.
    The thief may possess something he stole, but he does not own it.
    The owner has a right to take his property back from the thief.

    #2
    The LC72 is loaded with some kind of ball powder (WC852?). I also have some LC76 which is loaded with extruded (IMR or H 4895?) powder. I'll try a couple clips of the LC76 and see how that works. If it does, then it's just the and 72 that I'll have to work with.
    Last edited by Smokey; 10-21-2018, 04:20 PM.
    The thief may possess something he stole, but he does not own it.
    The owner has a right to take his property back from the thief.

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      #3
      With two clips of LC76, I had one short cycle. The LC68 would have two or more per clip. The LC 68 cartridges where I replaced the propellant with WW748 all cycled properly, so it seems the powder is the problem.
      Last edited by Smokey; 10-21-2018, 04:20 PM.
      The thief may possess something he stole, but he does not own it.
      The owner has a right to take his property back from the thief.

      Comment


        #4
        Forgot to mention, the rifle is a CMP Special that works great and ejects towards 1:00 o'clock with good ammunition. Its the older surplus ammo where I first had any problems of any sort. The rifle is thoroughly greased with Mobil 1 synthetic for what it's worth.
        The thief may possess something he stole, but he does not own it.
        The owner has a right to take his property back from the thief.

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          #5
          I just signed up and I can’t figure out how to post a new topic or start a new thread. I’m trying to find out what number is a good number to calibrate the elevation knob to after zeroing a battle zero at 25yds.

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            #6
            Originally posted by Film23 View Post
            I just signed up and I can’t figure out how to post a new topic or start a new thread. I’m trying to find out what number is a good number to calibrate the elevation knob to after zeroing a battle zero at 25yds.
            After you sign-on click on "Forum Home". Under Forum home there will be a directory of all the discussion areas. Click on the topic you want to discuss. ( for example, "Garand Discussion Area"). Look for and click on the "New Topic" button. Now you have the "Title" and "Write something" areas for your post.

            Welcome to the forum.

            Last edited by jak; 09-13-2018, 07:47 AM.

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              #7
              Smoky. LC is known for being alittle on the light side. I suspect as your newly parkerized rifle gets worn in it will cycle fine

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                #8
                I know Quickload is not the final answer but for getting some idea of port pressure it's better than most reloading manuals. WWII M2 ball was supposed to run around 2800fps. Using H4895 or IMR4895 with the M2 components and seating depth it calculates around 8900psi port pressure. My 180gr handloads with IMR4320 run around 8000 psi, a lot lower; and cycle just fine. I did read somewhere that later LC production ran 2650 fps. Backing the charge off to that velocity, I still get 8300 psi which should work just fine. I suspect the powder is deteriorating. The older stuff has more short cycles.
                The thief may possess something he stole, but he does not own it.
                The owner has a right to take his property back from the thief.

                Comment


                  #9
                  Further update, I tried some LC72 M2 Ball and got one very short cycle, about half ejected to about 4:00 o'clock.
                  In summary:
                  LC76 - Fires well, one in 16 short cycles
                  LC72 - Becoming weak with multiple "barely cycles"
                  LC68 - 2-3 short cycles per clip.

                  Guess I'll use up the LC76. The rest I'll pull down and load with new propellant. I may try loading additional "pull-downs" with well-mixed pull-down powder to see how that works.
                  The thief may possess something he stole, but he does not own it.
                  The owner has a right to take his property back from the thief.

                  Comment


                    #10
                    I pulled down 24 of the LC 68 ammo. They were loaded with 44.1 grains of an extruded propellant that looks like IMR or H4895. Using Quickload I get 2530 fps, and a port pressure of 7900 psi. In other words, pretty wimpy for 30-06 ammo. The primed cases were loaded with 147gr FMJBT and WW748 to around 2770 fps. They all fired normally and grouped to the best of my ability. Since ball powder is supposed to be harder to ignite, the primers aren't the problem. The LC 68 is loaded down and the powder seems to be deteriorating, though it all looks fine.

                    For reference, M2 ball was supposed to run 2808 fps. That gives a port pressure of 8868 psi with IMR4895, 8785 psi with H4895.
                    The thief may possess something he stole, but he does not own it.
                    The owner has a right to take his property back from the thief.

                    Comment


                      #11
                      Found two clips of LC 72 ammo. I pulled them down. They were loaded with 48gr of ball powder (WC852f ?). The powder was mixed and loaded back (at 47 gr) with 147grFMJBT bullets. Using Quickload and H380 data, I get 2500 fps and 7700 psi port pressure. They were quite mild shooting but very consistent with no short cycles and grouped acceptably. I'll try this with the LC 68 except load the extruded (H or IMR 4895) 47gr instead of 44 gr powder after mixing it.
                      Last edited by Smokey; 10-21-2018, 04:16 PM.
                      The thief may possess something he stole, but he does not own it.
                      The owner has a right to take his property back from the thief.

                      Comment


                        #12
                        The short cycles with the LC 76 were all on the first shot. Today I carefully removed every trace of oil from the bore (I usually just run a dry patch) and had no short cycles with the LC 76.
                        The thief may possess something he stole, but he does not own it.
                        The owner has a right to take his property back from the thief.

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                          #13
                          Used some more LC 76 ammo with no problems Sunday. Guess I need to really remove the oil from the bore using solvent. The dry patch just wasn't enough, though that was fine with my handloads.
                          The thief may possess something he stole, but he does not own it.
                          The owner has a right to take his property back from the thief.

                          Comment


                            #14
                            I looked at the headstamp for one cartridge in each clip, and separated out the LC 68 to rework them. Got a surprise after I started pulling the bullets. A couple had ball powder. Turns out the clips were a mix of LC 68, 72, 74 and 76. Never saw a mix of different year headstamps in a single clip before. I'll eventually mix the extruded power and load it into 16 rounds and see how that works.
                            The thief may possess something he stole, but he does not own it.
                            The owner has a right to take his property back from the thief.

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                              #15
                              Mixed the powder from some 100 pulled down LC68 cartridges well.
                              The original loads were pretty wimpy, far less than what full power M2 Ball at spec would use.
                              Loaded some of the "pulldown" empty cartridges with 3 grains more than they originally held using the mixed powder and 147gr FMJBT bullets.
                              They fired and ejected very consistently, and grouped fairly well on the target. No signs of excess pressure. Guess I'll be able to reuse the propellant from the pulldowns instead of throwing it out.
                              Last edited by Smokey; 11-04-2018, 04:55 PM.
                              The thief may possess something he stole, but he does not own it.
                              The owner has a right to take his property back from the thief.

                              Comment

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