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Rifle shooters/reloaders-Help

Discussion in 'Shooting Related Threads' started by snkypete, Jun 8, 2013.

  1. snkypete

    snkypete Member

    Joined:
    Jan 29, 1998
    Messages:
    133
    I was attempting to zero a new bolt action .223 with my usual reloads; military brass, cleaned, trimmed cases, 25.4 gr. 748 powder, 55 gr.spire point bullets. I was stunned to find very unstable rounds down range, one round "keyholed". I pulled several bullets from that group and weighed the powder charge. All were consistent, 25.4 grains.

    I went to factory ammo and zeroed rifle and scope perfectly. I am at a loss as to know what was causing the unstable rounds. Hadn't had that problem with those reloads before (that I know of). I suspect defective bullets, but that is just a guess. Two out of four rounds flew true, the other two went wild.
    Any suggestions?

    Richard
     
  2. halfmile

    halfmile Well-Known Member

    Joined:
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    Location:
    Green Bay Wisconsin
    You neglected to mention what bullet you are using.

    At any rate, if it is driving you nuts, you need a controlled experiment to find out what's going on.

    I used to use a lot of 748 in my Pdog rounds, great powder. One year I decided to go a little stiffer, and added a half grain to my load. Sighted them in in April and went out West in May.

    Could not believe what was happening. I couldn't hit the barn if I was inside. I had Johnny Boy spot for me, and when he saw TWO hits off one shot we figured it out. the loads were sitting in the sun and getting warm, which increased the pressure enough to make the SX bullets go fast enough to come apart.

    Solution: Rounds went in the cooler, and accuracy returned. Whew.

    If I were you I would try a different bullet first, with all else being the same. Your load is well within pressure limits and should not be a problem.

    Then try pulling some factory rounds and substitute your bullet. The only way you can get an answer is to switch stuff around toil you find the cause.

    Good luck.

    HM
     
  3. northern mist

    northern mist TS Member

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    Jan 24, 2013
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    Location:
    Harbor Beach, MI.
    You did not say what weight the factory rounds were, but if it is a bolt action I would check the rifling for twit rate. It may not be fast enough to stabilize the bullet. With 55gr. bullets you probably will need at least 1:10 to stabilize the bullet. From your description this is the track I would take.
     
  4. smoke-eater

    smoke-eater Member

    Joined:
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    Location:
    SW OHIO
    If your rifle is chambered for .223 do not use military 5.56 brass, it's not the same, it's thicker and requires the chamber to be cut different.

    Also, watch your case length.

    What twist is in it?
     
  5. Leo

    Leo Well-Known Member

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    Jan 29, 1998
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    I have done exhaustive volumetric and destructive testing on multiple lots of .223/5.56 brass. There is more difference between individual brass casings within the same production lot of LC or WCC military brass than there is between Military and commercial production brass. There is some differences of WHERE the web is thicker, but with equal internal volume, the brass does not change internal or external ballistics. The case thickness difference WAS in 30-06 rounds, and even in some of the Military 7.62 rounds. In my testing of 5.56 rounds, we went back as early as TW 1972 and every few years of LC, FC, and WCC up to current. The thicker brass cases in m-16 rounds is a myth.

    Chamber reamer patterns were different 30 years ago, with the military chamber having more leade. This has pretty much gone away as reamer patterns have become hybrids that are tolerant of either SAMMI spec. Again, this has difference with the bullet ogive to rifling relationship, something that should be monitored during reloading.

    One of the problems I am seeing with reloading right now is that since components are in short supply, a lot of junky bullets are hitting the market. WAY too many bags of bullets out there that are sold as "brand name out of a bulk pack". I also think a lot of production seconds are making it to market. Of course these are not sold in factory packaging. For a bullet to be accurate, it must be of a diameter to properly engage (and stay engaged) to the rifling. even .001" too small can seriously ruin accuracy. That is easy to determine with a micrometer.

    The second aspect is the uniformity of the bullet jacket and the concentricity to the core. This is very difficult to determine without cutting it apart. Remember that the little bugger is spinning well over 80,000 rpm, so even minute out of balance factors make a big difference.

    WW 748 is a good powder, it is, however temperature sensitive. I personally have not seen inaccuracy because of that, but I have seen loads that were safe and predictable in cool weather show pressure signs and velocity fluctuation over a chronograph if they get hot out in the sun. I compete with a guy that loves how 748 performs, and just carries his ammo to the line in a lunch box sized cooler when the weather is hot and sunny. H4895, Varget, Reloader 15 or VV135 have been proven very good in the .223 and are temperature tolerant.

    I would measure and weigh the bullets, and try another batch of bullets. If you need a test lot, the 52 gr Sierra Matchkings are a know good bullet. Nosler Custom Competition line is very good these days also. The Berger VLDs shoot really well, but are pretty sensitive to the bullet jump distance which would add another variable to your load.

    Good Luck
     
  6. jim brown

    jim brown Well-Known Member

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    If you are shooting a Savage you may have too fast twist for that bullet at that speed. I have a 223 Savage that over stabilizes anything less than a 60 grain bullet at full velocity. The keyhole thing is the clue indicating problem with stabilization. Savage puts about an 8" twist in their 223 barrels which is far too fast for light bullets. Mine will keyhole with 50 or 55 grain bullets. Either get some heavy bullets or drop the powder charge way back and see what happens.


    jim brown
     
  7. SYLHOUETTE

    SYLHOUETTE TS Member

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    748 can be a very finiky powder. does not like temperature changes and increases pressure very rapidly with a slight increase in powder charge. that is why the military got away from it. it was one of the origanal powders they tested for the 5.5 cartidge
     
  8. smoke-eater

    smoke-eater Member

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    LEO Thanks for the info on the brass, was not up on that...
     
  9. Neal Crausbay

    Neal Crausbay Member

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    Jan 29, 1998
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    Could be a cleaning problem. Remove all powder and copper fouling. Clean the barrel until you cannot get any stain on a clean patch after using Butch's Bore Cleaner and a good brush. Watch carefully for a blue stain indicating copper fouling. Don't give up until you get the barrel totally clean. Might surprise you.
     
  10. snkypete

    snkypete Member

    Joined:
    Jan 29, 1998
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    Many thanks to all who responded. I have a lot to work on and your suggestions have all helped a great deal. Now back to the reloading bench and some experimentation. You all have been very helpful and I appreciate it a bunch.

    Richard
     
  11. slic lee

    slic lee Active Member

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    Location:
    Miami Beach florida
    I didnt like what you said, went to Hodgdon reloading data, all data of 748 with your bullet has been removed.
    Call Hodgdon about 748. LEE