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  1. #1
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    Default Groups going from 1/4" to 3"

    Was out shooting the CZ 527 Varmint in 223 (1 in 9 twist) yesterday. I was shooting 1/8 to 1/4 inch three shot groups at 100 yards all day. When I went out to 200 yards my group sized increased to about 3 or 4 inches, not just once or twice, but with every group that I shot. Came back to 100 and they were all within 1/4 inch again.

    The load I'm using is a 50gr V-Max, 21.9 Gr of IMR 2198, CCI Small Rifle Primer, and C.O.A.L of 2.220. This is a load that I worked up for a 1 in 12 twist rifle, but it shot so well at 100 yds out of this rifle that I just stuck with it. Is it possible that the fast twist of this 1 in 9 twist rifle is over-stabilizing the 50 gr bullet, but only after 100 yds?

    I really don't want to have to go to a different bullet because I've had great success with the 50gr V-Max, but as most of my shots on whistlepigs are well over 100 yds I just may have to. Any advice would be greatly appreciated!

  2. #2
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    Default Re: Groups going from 1/4" to 3"

    50g projectiles are certainly in the realm of possibilities for a 1:9 twist gun. 55-62g is often thought of as the sweet spot for barrels of that twist. I don't think it's the projo alone.

    What were the conditions when shooting out to 200? Strong winds? How were you shooting? What was your setup? It sounds to me that it's environmental and not the gun/ammo combo.

    What scope are you using? What's the subtensions? Have you chrono'd the ammo for a consistency check?

  3. #3
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    Default Re: Groups going from 1/4" to 3"

    There was a fairly brisk wind, but I doubt it was strong enough to affect the bullets that much. I was getting some horizontal stringing, and it was actually going into the wind, not like the wind was pushing the bullets. I was shooting off the bench using sandbags. She's topped with a Nikon Monarch 5 3-15. I'm honestly not sure of the subtentions, butit's probably .25 to .375 at 100yds. I have not chrono'd the ammo. It's just odd to me that it shoots so well at 100, then goes to shit at 200. Gonna buy some heavier factory ammo next time I hit the range and see what happens.

  4. #4
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    Default Re: Groups going from 1/4" to 3"

    Your 1x9 twist is too fast for the 50 gr bullet.

    If you shoot at 300 yds or more, your groups will start to resemble shotgun patterns. While it may be accurate at 100 yds, at greater distance, it's start to spin out of control, causing greater shot dispersion.

    Take a look at this chart under the heading ".224", to the right of the yellow highlighted column - which is the diameter of your 50 gr. bullet. It shows the suggested twist rate you should be using:

    Attachment 97067
    - bamboomaster

  5. #5
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    Default Re: Groups going from 1/4" to 3"

    Quote Originally Posted by bamboomaster View Post
    Your 1x9 twist is too fast for the 50 gr bullet.

    If you shoot at 300 yds or more, your groups will start to resemble shotgun patterns. While it may be accurate at 100 yds, at greater distance, it's start to spin out of control, causing greater shot dispersion.

    Take a look at this chart under the heading ".224", to the right of the yellow highlighted column - which is the diameter of your 50 gr. bullet. It shows the suggested twist rate you should be using:

    Attachment 97067
    That's really what I was thinking too. Guess I'll have to invest in some new bullets... Back to load development I guess.

    So... change of topic. Anyone know of a good bullet in the 65-75 gr range for poking varmints?

  6. #6
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    Default Re: Groups going from 1/4" to 3"

    Look here and take your pick! And don't use any "pulled" surplus sh!t for the distances you're shooting...

    https://www.wideners.com/reloading-s...ts/223-bullets
    - bamboomaster

  7. #7
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    Default Re: Groups going from 1/4" to 3"

    Quote Originally Posted by bamboomaster View Post
    Look here and take your pick! And don't use any "pulled" surplus sh!t for the distances you're shooting...

    https://www.wideners.com/reloading-s...ts/223-bullets
    I'm a big fan of the Sierra 69 Grain HPBT MatchKing out to 300 yards.
    Toujours prêt

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    Default Re: Groups going from 1/4" to 3"

    I respectfully disagree... if the bullets didn't like the 1n9 twist... they wouldn't shoot well at 100yds.

    I believe it was the wind.

    As for different bullets...

    I suggest these... Un-Cataloged Hornady bullets... But danged accurate.

    https://www.midsouthshooterssupply.c...lure-500-count

    Read this thread.

    http://www.m4carbine.net/showthread....-62-grain-BTHP

  9. #9
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    Default Re: Groups going from 1/4" to 3"

    Quote Originally Posted by bamboomaster View Post
    Your 1x9 twist is too fast for the 50 gr bullet.

    If you shoot at 300 yds or more, your groups will start to resemble shotgun patterns. While it may be accurate at 100 yds, at greater distance, it's start to spin out of control, causing greater shot dispersion.

    Take a look at this chart under the heading ".224", to the right of the yellow highlighted column - which is the diameter of your 50 gr. bullet. It shows the suggested twist rate you should be using:

    Attachment 97067
    This chart can not be accurate, IMHO.

    How is it that MIL shoots 62 and 77gr, both out of 1:7 barrels, when by this chart 62 gr is best suited fo 1:12?

    Wasn't M855 (62gr.) developed at the transition of the M16a1 to A2 (1:12 twist to 1:7)?

    http://www.rimfirecentral.com/forums...d.php?t=557097

    Theres even a guy with the same rifle as OP shooting 50gr with excellent results.

    Similar results here: http://www.ifish.net/board/showthread.php?t=445775

    And here: http://forum.accurateshooter.com/thr...llets.3881234/

    These were my first three results from googling the question.
    Last edited by ianb1116; May 16th, 2017 at 02:49 PM.
    I'm only here for the wood c-rings.

  10. #10
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    Default Re: Groups going from 1/4" to 3"

    Quote Originally Posted by ianb1116 View Post
    This chart can not be accurate, IMHO.

    How is it that MIL shoots 62 and 77gr, both out of 1:7 barrels, when by this chart 62 gr is best suited fo 1:12?

    Wasn't M855 (62gr.) developed at the transition of the M16a1 to A2 (1:12 twist to 1:7)?

    http://www.rimfirecentral.com/forums...d.php?t=557097

    Theres even a guy with the same rifle as OP shooting 50gr with excellent results.

    Similar results here: http://www.ifish.net/board/showthread.php?t=445775

    And here: http://forum.accurateshooter.com/thr...llets.3881234/

    These were my first three results from googling the question.
    Just read those threads, and they pretty much all talk about 100 yard accuracy. My 100 yard accuracy is not the problem. If I was only shooting the gun from the bench at 100 yards I would be more than happy with the 1/4" groups I was getting. The problem is that when I take shots further, my accuracy suffers dramatically. Hell, if I wouldn't have shot this thing at 200 yesterday I wouldn't have any reason to complain (not that I'm actually complaining, just looking for answers to a perplexing question). All I know is that SOMETHING is happening between 100 yards and 200 yards that is causing bullets to string. I'm gonna buy a box of factory 62 and 69 gr bullets and see if accuracy is any better at distance with those. Don't want to get into throwing this load away completely yet. Who knows, maybe I just plain old was having a bad range session at 200 yards.

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