7mm RUM a-max problem

Discussion in 'Reloading' started by docp, Mar 13, 2010.

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  1. docp

    docp New Member

    Jan 13, 2008
    I went shooting today and decided to check my zero on a Remington 700 w/ 1-9 twist Pac-Nor 3 groove. My load is 85 gr. of Reloader 25, Fed match primer, 162 A-max bullet .020 off the lands. Conditions were: Overcast with temps in the low 50's w/ 92% humidity.
    First group 10 MOA high and 3" @ 100 yds.. This from last fall's 200 yard zero and 3/4 MOA or better groups.
    Adjusted zero 8 MOA down and shot 3 more. 3" plus.

    Started another group. 1st shot 6 MOA low. #2 OFF the target altogether! #3 was 2 FEET right and 1 foot low. Bullet tore a jagged hole in the paper.

    This barrel has less than 100 rds. down the tube.
    Bore scope shows excellent interior. Lands in great shape. Throat is fine. crown is fine. I can find nothing wrong with the rifle. Mark 4 seems to track fine. all bolts and screws torqued on scope and action.

    Could this bullet be coming apart, because that is how it is acting. I find that hard to believe, so if anyone has thoughts, I'd like to hear them.
    Last edited: Mar 14, 2010
  2. jeffro

    jeffro Well-Known Member

    Nov 15, 2006
    I would check your scope. Sounds like you have a scope issue. Guns dont change that much even with different loads.
  3. phorwath

    phorwath Well-Known Member

    Apr 4, 2005
    That jagged hole in the paper is a telltale sign the bullet is coming apart or not stabilizing properly.
  4. kiwi3006

    kiwi3006 Well-Known Member

    Aug 1, 2007
    Do a search on here for 3-groove barrels. I know Kirby posted up about problems he was having with 3-groove barrels tearing up bullets with thin jackets.
    You might have to try the 175 sierra match king, it should hold up better.

  5. docp

    docp New Member

    Jan 13, 2008
    Thanks for the input. I will look into 3-groove barrels. 175 Matchkings on the way. :)
  6. ahuntnfool

    ahuntnfool Member

    Mar 16, 2010
    Hi all,
    I am new to the LRH forums, but have read alot of useful info in these threads.
    I am with jeffro on the check your scope out.
    I just had a Winchester model 70 in 270 wsm with a Leupold 4-12x40 on it that did exactly what your gun is doing,and I also have a Remington model 700 sps in 300 wsm with a Burris fullfield 2 on it in 3-9x40 and it was doing the same thing.
    I took both scopes off and sent them in to the manufactures and when I got them back and put them back on..... well sub moa @ 100 yards with both guns.
    Last edited: Mar 16, 2010
  7. Iron Worker

    Iron Worker Well-Known Member

    Apr 3, 2004
    I bet your scopes are just fine. Its the thin jacketed bullets they're being ripped in the 3 grove bbl.Try a thicker skinned bullet