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Thread: 75G A-Max .223 bad grouping.

  1. #1

    75G A-Max .223 bad grouping.

    Guys this is bugging me, so i thought i would throw it out their so see if someone can help.
    Ive always used 60g vmax and have loaded 75 amax using varget powder. 60g Grouping spot on at 2 hundred yards, 1 inch high at 100 yards, but the 75 a-max is way way way off the mark, 5 to 6 inches low at 200 yards, so obviously something is not right. Its the same as the 60 at 100 , 1 inch high, all the range wrok was carried with zero wind conditions and on a level eye to target. Now my twist is 1:8 which is well capable for the 75 a-max, varget powder used was 23g, minimum being 22.5 and max 25g according to hodgdon data, so i not even overloading the case. Any help would be appreciated. Is it the powder, ie to fast a burner, do i need slower burn rate powder.?
    Last edited by mayfly; 21-06-2011 at 18:12.

  2. #2
    It definitely sounds like you have a velocity problem. I assume that your group size with the heavy bullets at 200 yards is twice as big as at 100 - Just low compared to the light bullet and also that you are using a "normal" length barrel not some super short one.
    From Hogdon's online Varget loading data, interpolating between their starting & max charge loads your bullets should be doing 2720 ft/sec. I ran my ballistic software (very old Sierra3) and that indicated that you should be about 2.7" low at 200 yards when 1" high at 100 yards (150 yard zero).
    Buy yourself a chronograph - a speed check is the way to go.
    HTH Ian

  3. #3
    sorry forgot mention, rifle is a tikka t3 lite, 20" barrel for this rifle as per factory. Yes the grouping is low and spread out.

  4. #4
    Have you checked that you do actually have the 1:8" version as opposed to the 1:12"? A buddy was assured by the dealer that his new Tikka was 1:8", but a while later he found it was actually the 1:12" version when checking with a cleaning rod.

  5. #5
    no its def 1:8 its on the barrel.

  6. #6
    to be honest as you know a 75gr bullet is a big lump for a .223 to be pushing and even tho you rifle is up to the job with its fast twist rate it still cant beat gravity and a drop of about 6" would be what i would expect and the only way i think you will get it to fly flatter is to get it going faster

  7. #7

    I have a similar problem. Laurie Holland is now a site member and he might have an answer, I pm'd him yesterday with this exact problem. 20" barrel might be a tad short. You need to read his article in target sports 26/10/09. In this article best powder for 75 a max was H4895 and reloader 15,

    The article also states that a 80grn V max runs well with Varget, however I can't find this bullet listed in my Hornady catalog. 23,5 gn Varget seems popular load for 75 a max.

    Will do some more searching


  8. #8
    Take it you don't have a chrono?
    Even with the twist you may not be driving them fast enough out of the 20" barrel.
    Try stoking it up a bit (worked safely) as you are at the bottom end of the load spectrum there.
    And of course there is always the greenhill formula...

    I have got 77gr stabilised in a 1:9 20" but it was too hot a load to be sustainable.

  9. #9
    If you are getting good results with the 60's whats your reason for change??? If it aint broken.........

    Have you tried H322 a proven 223 powder with superb results???

  10. #10
    Whoops looking in wrong catalog, they do a 80grn A max.

    If I load 75grn A max I use remington 7.5 primers as normal CCI pop. Also with varget dependent on the case your looking at compressed loads. COL might also be a problem. I think you will have problems with a 20" barrel as well.

    Try a google search on heavy bullets in the 223 remington which will give you some info.

    Bruce Potts did a .223 article in ST 10/04/08 suggested that with 75grn A Max 23grn Vit N133 was v accurate and produced 2,811 fps


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