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  • #16
    Suggest a good cleanup of the brake. Get the most carbon out of it.
    The maker of my brakes says to keep the brake chamber clean of carbon and that excessive carbon can effect accuracy.
    Is this brake used just on this barrel or also on other barrels?
    "The United States Marine Corps is a drug and I am a recovering addict."

    "American by birthright… U.S. MARINE by the Grace of GOD!"

    "And on the 8th day God created Marines and like fish, we came from the sea!"

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    • #17
      Rocky brought up an excellent point of a malfunction I had pretty much forgotten about!
      How many rounds do you have on the firing pin spring??
      Had a great rifle go bad due to that wayyy back.
      When the hammer drops the BS stops.

      Don't let them beat you down with their inexperience.

      You won't know until You Actually try it.

      The impossible just takes longer.

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      • #18
        RD, all valid points. I can confirm the action is not the issue. Bolt is stripped and inspected regularly when the action is cleaned, which is pretty much every time it comes home. I am very conscious about shooting fundamentals - always the first assumption when things are not going well. Pockets cannot be uniformed (Lapua is slightly deeper than any spec uniformer), but the flash holes have been uniformed and chamfered from the inside. Chassis has a built-in level.

        DM, I cleaned the brake this evening. It did go a little longer between cleanings than normal. I suspect the buildup was the result of getting oil on it somewhere along the lines. It could very well be the issue as I could not see it from the normal inspection without taking it off. The brake is a 6mm, and went from the original barrel to this barrel (does not get transferred intermittently).

        P100, slightly over 3,200 rounds; nothing significant. Action and trigger are not stock components - spring will see over 20k rounds before it even needs to be considered for PM replacement. The remainder will easily last into the 10's of thousands.
        Friends don't let friends shoot factory ammo.

        Continuous effort - not strength or intelligence - is the key to unlocking our potential.
        -Winston Churchill

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        • #19
          I was shooting mostly at 300 yards because 100 showed me nothing and 200 was getting easy.
          I really saw a difference in using a brake and not at 300 for the first 20 rounds all was good with the brake on and after that accuracy went south.
          When i took the brake off my barrel had carbon on the crown and after 2 outings with that happening I quit using the brake and no more carbon and no more odd ball accuracy issues.

          I am curious as to how it will work out after you get it all cleaned up.

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          • #20
            swampratt I too have experienced carbon in the brake causing issues. When I first started using them I left the brakes on when I cleaned the barrel to 'patch out' the inside of the brake. I would then treat the brake the same as I did the outside of the barrel - wipe on/off a thin coat of Hoppe's. I learned pretty quickly that anything (oil, solvent that leaves a residue, Q-tip fibers, ...) in or on the brake will collect carbon like a magnet and throw the bullet off. It was pretty easy to figure out what was going on since the problem came on suddenly, a quick glance at the brake revealed a mess, and it was with well developed loads.

            I am guessing the last time I wiped the crown I must have gotten cleaner on the barrel threads which made its way to the inside of the brake. I am basing this on the flaking on the crown since the initial wipe off of the carbon left the normal pattern indicating that something happened after it had been fired for a bit, which likely coincides with around the time that I finished shooting the break-in loads. I don't know that it explains why the low velocity loads shoot and the higher velocities scatter, but at the same time I don't understand pressure and gassing enough to say that it is or is not normal.
            Friends don't let friends shoot factory ammo.

            Continuous effort - not strength or intelligence - is the key to unlocking our potential.
            -Winston Churchill

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            • #21
              that seems like a lot of build up to me.
              I know oil will add to it, but I don't get that much build up in my brakes shooting cast bullets [and they throw oil everywhere] at the muzzle.

              anyway if the carbon clean doesn't settle it down and keeping it clean doesn't keep the flyers away, I would turn my attention to the brass looking at neck tension and anneal consistency from case to case.

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              • #22
                The vast majority of what you are seeing contour wise it the brake design. APA LB has some pretty crazy stuff going on. If you look close and follow that carbon to the end you will see a black lip. The carbon built up on the lip and worked backwards. Other than that section the rest looks better than my 6.5 and 308 brakes do before they get cleaned.

                Annealing is consistent unless my AMP is on the fritz.

                I am not aware of neck tension causing carbon buildup. Seating pressure is at 30. Are you suggesting I increase or decrease?
                Friends don't let friends shoot factory ammo.

                Continuous effort - not strength or intelligence - is the key to unlocking our potential.
                -Winston Churchill

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                • #23
                  Posting an update now since it does not look like I will make it to the range this weekend.
                  • I re-ran the Aztec testing. All 3 test pieces produced the same number however I got a very different number (code 6259) than I did a while back when I tested from this same batch of brass (code 0569). I wish I knew what AMP's method of assigning the numbers is. For all I know that use an internal run clock as a factor when coming up with the thing. Anyway, that is something.
                  • I stripped the rifle down sans barrel from the receiver and double, then triple check everything. I really did not want to clean the barrel but I did that as well.
                  • I decided to re-check the CBTO. I used the original method that I used the first time and got the same numbers as the first time with both types of bullets. I then used Litz's (not sure if he really came up with it, but it was his article) only with a fully stripped bolt except the extractor and 5 lbs of seating pressure rather than what he describes as 'loose' and got a different number. I must say that I have more confidence in the second method.
                    • Original for 105 Hybrid 1.8490, new 1.8695
                    • Original for the 110 SMK, 18470, new 1.8595
                    • Neither of the differences are mind numbing, but I am going to run with the new numbers
                  For those that are interested, I modified neck tension down that far by starting with a sized piece of brass that had 0.0002 of runout in the middle of the neck, seated a bullet deep, pulled the bullet with an intertia puller, then reseated and pulled it several more times (think it was 5 total). I then used a new bullet for the testing. 3 out of 4 tests with the 105 gave the exact same number with one being 0.0005 off. 3 of 3 tests with the SMK gave the exact same number.

                  I am still going to work up some loads as mentioned above, but at this point I am pretty confident that I have everything covered other than pulling the barrel.
                  Friends don't let friends shoot factory ammo.

                  Continuous effort - not strength or intelligence - is the key to unlocking our potential.
                  -Winston Churchill

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                  • #24
                    I did some annealing tests with .308 cases and checked seating pressures. spinning 9 seconds in the flame vs 20 I got the same seating pressures but when i made the entire neck glow bright red which took a long time in the flame that is when seating pressures changed.
                    I have noticed improved accuracy in my 30-06 with more neck tension. .015" was so so on accuracy and .003" was the sweet spot.
                    Too little pressure and you could unseat the bullet when chambering or possibly when Primer ignites. I have read the primer thing but not tested it for fact.

                    45 psi In my winchester annealed cases for .308 was excellent and is the lowest. My Lapua cases are in the 80-85 psi area.
                    They both shoot excellent.

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                    • #25
                      The only tools I use for checking where the bullet is in the lands is a case with shot primer in it and standard neck tension is fine.
                      I color the bullet with a sharpie Permanent marker and insert it into the chamber and close the bolt on it and then remove it.
                      I look for marks on the bullet from the lands.
                      If none i take the inertia puller and load the round into it and pound it longer.
                      After i get marks on the bullet I seat the bullet deeper into the case until I get to the point of no marks.

                      I must color and clean and recolor the bullet a few times.
                      I have found you can be touching the lands as much as .030" Basically have .030" long land marks and the bullet is not to a point of being in solid.
                      Touching and bottomed out I have found are 2 different things.
                      5 PSI would bottom it out I bet.

                      I have a friend that shoots F class and seats his long by .030" after bottoming out.. that way when he chambers the round it is actually seating deeper into the case and is jammed into the lands.
                      But each bullet will be exactly in the same spot and if any case sticking was present from say old loads it will remove the sticking equation.

                      Not what I want to do..but I build hunting loads not F class.
                      I like my bullets .005" from any marks being made on the permanent marker painted bullet.

                      But I was given some Bergers and those wanted to be .060" from the lands to make them group very tight.

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                      • #26
                        I get the hesitation on 5 being too much, but I did seat empty cases after using normal tension and the bolt handle drops free just after the lugs engage. You can also pull the bullet forward a bit just using a firm grip with fingers. Not much resistance on the bolt at all, and I am pretty sure if the bullet was jammed it would pull back out a little when removing making it really hard to get a repeatable value.

                        I was using a marker to check the original way, but I have a hard time with Bartlein barrels or maybe it is just this reamer. Anyway, if I get it to where there is no mark then push the bolt handle forward when it is engaged to simulate part of the pressure the case would have from the ejector, I get a couple wipe marks (not a good edge) that causes me to question where it should be so I do it a bunch of times and take the average.

                        Will see what happens.
                        Friends don't let friends shoot factory ammo.

                        Continuous effort - not strength or intelligence - is the key to unlocking our potential.
                        -Winston Churchill

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                        • #27
                          Could this be the problem?

                          I started to resize the same brass from the last outings and immediately found the die lock ring was walking. It had enough play that with a little testing is was bumping the shoulder 0.0 - 0.003. At the very least is makes me wonder if this is why my shoulder measurements were all over the place after firing. Never crossed my mind that it may have come loose as I check the first few pieces of brass each session, adjust if needed, and then get to it.
                          Friends don't let friends shoot factory ammo.

                          Continuous effort - not strength or intelligence - is the key to unlocking our potential.
                          -Winston Churchill

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                          • #28
                            Yep it will make a difference you will see. I experimented with .0000 shoulder movement and .002" and .008" differences you can absolutely see on paper.
                            I take a sharpie and mark my die with a line and that line lines up with another line I drew on the top of my press that leads right up to the die.
                            I can see if anything moves.
                            Not saying that is your issue but 1 more variable you can eliminate.

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                            • #29
                              yes it could be.
                              the firing pin would be banging into the case in a different way each trigger pull affecting the barrel harmonics.
                              or at the minimum where the bullet is in the case when the pressure rises enough to get it moving, it would basically mimic poor neck tension variation.

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                              • #30
                                golong,

                                This might sounds crazy BUT I used to shot NRA High Power Silhouette with a couple former BR shooters.

                                Now since they were single shot loading, they did not seat the bullet with a die, they left it long and seated it when chambering. This insured the bullet had zero bullet jump which can sometimes be a problem.

                                Just tossing that up into the air.....
                                "I am, therefore I\'ll Think."- John Galt "Atlas Shrugged"

                                "Arguing with a Marine is like wrestling with a Pig. Everyone gets dirty, but the Pig loves it."

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