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Thread: C.O.A.L testing

  1. #1
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    Default C.O.A.L testing

    Just to start this off I had to do all the testing at the mercy of mother nature there are going to be a difference in the weather ect. I bought a Winchester Model 70 Extreme weather a month or so ago. I got time to reload for it so I decided to do a little experment with it and move the bullet back farther by .005 every time. I got my reverence point with a Hornady O.A.L gauge and modified case. I decided to use 165 grain Nosler partitions, because I got a ton of them from shooters pro shop as seconds. The powder I used was IMR-4350, because that is what alot of people use for the old 06.
    A little about the rifle. It is a plan Jane Winchester model 70 with talley rings and a VX3 2.5x8x36. When I got it home I gave it a good cleaning and used JB bore paste and ran a patch though 100 Times. I did adjust the trigger down as far as the factory trigger would let me. I torqued the front screw to 35 Inch Pound and the back one to 25 inch pounds. That is all that I have do so far to the rifle itself. I did clean it after every depth string with whip out till I got no blue or black on the first patch.
    Brass prep was full sizeing new Winchester brass was a RCBS die. Trimmed them all to the same lenght and put them in a tumbler over night. The number you see on the side of the groups is grains of powder.

    All targets where set at a 100 Yards with my range finder

    My first day out at the range I was shooting with the bullet .015 off the lands. It was 5 degrees out and just a light wind. Not even enough to worry about. As you can see my best group was 55 grains of powder.
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    My next time out the range I moved the bullet to .020 off the lands and it was about 5 degrees again. This gave me my best group at 56 grains of powder. It shot right around .025. no wind

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  2. #2
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    My next time to range I shot .025 off the lands. As you can see the groups are not good at all. The temp was 0.

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    My last session at the range I shot .030 off the lands. It didn't group very well either. The temp was 32.

    I didn't see the need to go back any farther as the groups where getting worst. I found this intersting that just .005 will make a big difference.

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  3. #3
    Member markopolo50's Avatar
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    I would not have guessed that .005" would make that much difference either. I have limited experience handloading and appreciate the info here. So 56grains at .020 off the lands looks like the winner. Set her a couple three inches high at 100 and let her rip. Very nice, thanks

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    The one thing about 3 shot groups is that they may not give a good statistical picture of what is really going on. Try the experiment again and see what you get? The key to accurate shooting is repeatability. Nice consistent work up and you have a nice shooting gun it seems. It seems funny that .005 would make that much difference. .05 for sure. The next time out, was everything the same as before, did you resize the brass or use the virgin sized brass?

  5. #5
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    I bought 100 brass and then ran them though the full lenght die then trimmed them all to the same lenght. I shoot them all once and then start over a avian till I go though all the pieces. That way some don't get shot more then others.

  6. #6
    Member kodiakrain's Avatar
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    That is pretty interesting, appreciate all the detail you've posted on your test

    if you get the time and weather, I also would like to see more of the same, with larger than three shot groups,
    just to see it

    COAL, is the one thing that just about wrecks my sleep,
    wondering how much difference it must make to everything else

    Cool Thread
    Ten Hours in that little raft off the AK peninsula, blowin' NW 60, in November.... "the Power of Life and Death is in the Tongue," and Yes, God is Good !

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    Moderator stid2677's Avatar
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    I would be curious to see some .005 and .010 groups. I get my best groups with both Accubond and Partitions at .005
    I made a recording error and when I loaded up a new batch I mistakenly seated them at .050 instead of .005 and they would not group at all. Once they were back to .005 they shot one ragged group.

    I think many people over look COAL as an important part of loading.

    I too thank you for your time and effort. Well done Sir!!!

    Steve
    "I refuse to let the things I can't do stop me from doing the things I can"
    Founding Member
    http://www.residenthuntersofalaska.org/

  8. #8
    Member marshall's Avatar
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    COAL testing is worthwhile. I like to test three shot groups in .025 increments to conserve time and parts. One group will always stand head and shoulders above the rest. That group can then be tweaked .010 on each side of the best COAL in the first test to narrow it down. One of those may or may not be better. If it is better it can be further reduced .005 each side for a final test.

    Take a look at six identical powder charges with only changes in COAL. Test target number three is the winner, no further testing required. This was 300gr TSX testing on a 375 Ruger.

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