First Ladder test

Discussion in '7mm STW' started by WapitiBob, Feb 1, 2014.

  1. WapitiBob

    WapitiBob Well-Known Member

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    I've been spending most of my time at 400, thinking 200 was pretty much dialed in. The problem has been that my groups opened way up at 400. I normally load 73.0 gr but brass isn't lasting and any more than 73gr will leave an extractor pin mark on the head and tight bolt.

    I'm shooting 180 Berger hunting VLD's, .015 off the lands.


    400 yards
    front bipod and rear bag
    cold, snow flurry, no wind
    shot low charge to high, twice thru
    RL-25, 215 primers
    once fired brass, no body sizing, shoulder touched but not bumped

    I'm thinking 71.5 to 72 is where I need to shoot another string?
     

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  2. thekyrifleman

    thekyrifleman Well-Known Member

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    Sounds and looks like you need to back er' down a couple of grains. Extractor marks and hard bolt lift should make you cease fire after the first occurrence... Imagine the possibility if you shoot that load on a warm day!!:-(
     
  3. ShowMeShooter

    ShowMeShooter Well-Known Member

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    71.5-71.8 looks pretty good to me. Did you still have a sticky bolt with these two charges?
     
  4. WapitiBob

    WapitiBob Well-Known Member

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    No, I dropped down to 72.5 a few days before this and shot a little bit and the brass looked like it hadn't been fired.

    73.0 didn't leave any marks or heavy bolt either, just a light stretch mark ahead of the belt. It's over 73 that was a problem. Well, except that at 73 the brass wouldn't last.
     
  5. ShowMeShooter

    ShowMeShooter Well-Known Member

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    Unless you are dead set on the extra velocity, I would drop back to the 71.5-71.8 and load 6 of each, shoot 2 groups of 3, pick the better performer and stick with that. I have used the Dan Newberry method (very similar to the ladder) several times and get good results. 59.1 grains of 4831 in my .270 very rarely sends a high or low shot in the group. Most of the time if a shot is out of the group either I pulled it or missed my wind condition.
     
  6. WapitiBob

    WapitiBob Well-Known Member

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    I liked the velocity at 73 but 2 firings out of $1.50 brass tends to temper the enthusiasm. In the end, a cpl hundred fps doesn't mean much if you're shooting 6" groups at 400 yards.
    I appreciate the info and will try those loads this weekend.
     
  7. Mowdy Ag

    Mowdy Ag Member

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    Agree on the 71.5 - 71.8. If you can confirm that performance with another range trip, I would call it good.

    MA
     
  8. WapitiBob

    WapitiBob Well-Known Member

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    71.5 gr RL-25 @400 yards, 2" dot.
     

    Attached Files:

  9. ShowMeShooter

    ShowMeShooter Well-Known Member

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    At 400 yards I'm not sure what else you could ask for.
     
  10. Solaction

    Solaction Member

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    Now that you've found the node I'd play with seating depth. Start on or just off the lands or the max to still get it in the magazine and go 3-4 thousand's in from there to a few thousand's in from the depth your shooting now and see what happens with say 3 shot groups. That's a good group you've got there but I bet it'll get better.