Smaller groups with Norma brass

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by gcamp54, Apr 23, 2011.

  1. gcamp54

    gcamp54 Well-Known Member

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    Feb 28, 2009
    I was very happy after the last trip to the range. I bought this used rifle and scope last summer as a back-up because I'm still waiting on my custom rifles. It's a Gen I Sendero in 300WM with a Mk4 scope. It shot about 2moa initially using HSM factory ammo with 190 BTHP. I then skim bedded it, re-crowned the barrel, replace the trigger with a basix, and replaced the firing pin assembly with a Tubbs. Got it down to about 1.25moa. Then using the same Winchester brass (after prepping brass) reloaded 190 VLDs with 79gr H-1000, 215m primers, with a .005 jump. Got down to about 1moa. Then I used the same load with new Norma brass. The only thing I did to the Norma brass was uniform the primer pocket and chamfer the neck. Got it down to about .5moa. Attached is a picture of the rifle set up with bipod and rear bag. I used this set up off the bench for the 100 yd group and used the same set up prone on the ground for the 200 yd group. You can see the big difference between the Winchester brass and the Norma brass on the 100 yd target. The 2nd 3 shot group with the Norma brass on the 100yd target was rushed due to someone wanting to go down range.

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    Rifle set up. Unfortunately no this is not my range.

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    100 yd target, from the bench, showing difference in W-W brass and Norma brass

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    200 yd target, prone. The out of group shot was my 1st and I new I pulled it so didn't count it in the group. The next three all felt good. Using norma brass. Ran out of loaded W-W brass.
     
  2. ICANHITHIMMAN

    ICANHITHIMMAN Well-Known Member

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    Jan 31, 2008
    Great little write up and nice rifle. I too have noticed that buying high end brass makes a huge diffrence in my group size.

    On your groups you can do much better in my opnion. Have you tried Erics seating depth test yet? It realy helped me and I use it all the time now.

    Jon
     

  3. gcamp54

    gcamp54 Well-Known Member

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    Feb 28, 2009
    No I haven't. This is just going to be my back up for now and I didn't want to expend a lot of time and money right now. I will in the future though. Especially since you brought it up. My next step is to shoot all the new brass then just bump the shoulder a little, prep the brass and see what once fired brass does.

    Gordon