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First reloads for G20

Discussion in '10mm Reloading Forum' started by rvrrat14, Jul 15, 2012.

  1. rvrrat14


    Sep 21, 2010
    Central Texas
    South central Texas
    82 degrees in AM and rising
    Wind S 5-10

    Starline brass
    165 gr GDHP
    AA 9

    Tested 14.8, 15.0, 15.2, 15.4. 10 shots each.

    No signs of pressure or smileys on any.

    Chrony results.

    14.8 AVG - 1297.0
    15.0 AVG - 1281.6
    15.2 AVG - 1271.5
    15.4 AVG - 1302.0

    Can't explain why 14.8 was higher. It also grouped better. All powder was dispensed with RCBS Chargemaster Combo.

    Will retry 14.8 and 15.4 for accuracy. Today was about velocity and pressure signs. More focused on not hitting the chrony than hitting the target! Both these loads showed groupings of 1/2" to 1 1/2" at 15 yds. Worthy of retesting.
    Last edited: Jul 15, 2012
  2. Taterhead

    Taterhead Counting Beans

    Dec 13, 2008
    Boise, Idaho
    Interesting chrony readings. Higher, lower, lower, then highest.

    They were generally in the ballpark with what I have seen, if not a wee bit slower. I wonder how close you were to the chrony? There might be a bit of chrony "noise" in the numbers if you were too close. I would suggest backing up a bit.

    I have shot my diffuser rods on my chronograph. The best thing I have found is to put a target behind it. "Aim small, miss small". Ha! It has been quite a while since I hit my chrony.

  3. It happens to me occasionally that a bit lower charge batch goes some faster in average. It's probably inconsistent powder drop or/and inconsistent neck tension on brass issue.
    Hand weighing each charge and weighing brass cases would help to solve that problem, but that's what reloaders have to do for long range shooting reloading. I won't bother with that for pistol shooting.
    Last edited: Jul 16, 2012
  4. rvrrat14


    Sep 21, 2010
    Central Texas
    Chrony was 5 feet. Many years ago Pact tech advised 4-8 ft.
    Did have some anomalies with brightness when I started. Set up umbrella over screens and all was good.
    Have never had this issue in 28 years of reloading. Challenging. Just means more shooting.
    I will cross check powder charges with manual scale. COAL is 1.255 and all loads taper crimped same.
    Last edited: Jul 16, 2012
  5. firefighter4215


    Nov 2, 2009
    I've never shot the chronograph, but I too managed to shoot a diffuser rod once. I quickly replaced those metal rods with wooden dowels. I haven't shot any of those yet, but I figure they'll break instead of just bending, which should keep the chrono from flying off the box I set it on. I usually put it out at fiftwen feet, too. I thought I'd read somewhere that muzzle flash could mess with the readings if it was any closer than that.
  6. rvrrat14


    Sep 21, 2010
    Central Texas
    Rechecked chargemaster pro with manual scale. Right on the money. However......noticed when u calibrate scale and zero tare weight for pan, you'll get different readings if you leave cover open or closed around the pan. Possibly reason for anomaly on prior test loads. Will start over with same strings: 14.8, 15.0, 15.2, 15.4.
  7. _The_Shadow

    _The_Shadow Ret. Fireman

    Jul 23, 2007
    Southeast, LoUiSiAna
    Try this for your CHRONY...Re-purpose Ironing Board Chrony Stand
    Here is some things I did with a "FREEBIE from the curb Ironing Board", CHRONY mounted with wing nut, Flip-Up Target Stand, mounted on backend, and the sacrificable diffusers are made from water/milk jugs. Take a gallon water jug or milk jug, cut an 2 1/2" strip around the circumference of the lower flat square section.
    Then cut 90 degrees accross the middle of one of the wide flat sections, then fold in half and cut at 90 degrees again yielding two pieces of equal length about 11" long each. Now use an "ice pick" (or simular) to push a hole in the middle of each end about 1/4" in from the edge for the bamboo skewers to slide into the holes. There you have it very simple and a freebie! [​IMG]

    This piece of plate helps with CHRONY protection
  8. rvrrat14


    Sep 21, 2010
    Central Texas
    Cool ideas. Thanks Shadow.
  9. rvrrat14


    Sep 21, 2010
    Central Texas
    Finally revisited the 10mm loads. Chrony was placed 12 ft away. Here ya go....

    165 gr. GDHP
    AA 9 - 14.8 ,15.0, 15.2, 15.4

    14.8 - 1226.6 fps
    15.0 - 1242.0 fps
    15.2 - 1256.4 fps. MOST ACCURATE LOAD
    15.4 - 1270.4 fps. 2nd accurate load

    Stock Gen 3 Glock 20.
    Last edited: Aug 25, 2012