308 with 220SMK

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Dog Duster, Feb 25, 2005.

  1. Dog Duster

    Dog Duster Member

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    Jan 9, 2005
    Anybody have a good starting load for a 308-220SMK. I keep hearing the 220 Matchkings just float after they go subsonic. Been there done that??
     
  2. shaner2121

    shaner2121 Active Member

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    Jul 14, 2002
    I've done some cooking with the 220 in an 300 ultra. Need a 1 in 10 twist, very accurate. sorry thats all I can help you with. Good luck.
     
  3. Dog Duster

    Dog Duster Member

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    Jan 9, 2005
    Well Shaner, the 1 mile matches in Iowa start in April, I guess I'll give it a try. The word is they are stable when they go trans-sonic. I guess we'll find out..DD /ubbthreads/images/graemlins/cool.gif
     
  4. abinok

    abinok Well-Known Member

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    Nov 25, 2004
    I am shooting 220SMKs out of a 300WM. They shoot very well subsonic. Ive shot out to 1610, in conditions that my computer says the bullet will go subsonic at around 1350.

    BL-C(2) From 35.0 grains to 38.0 grains 2250fps
    H-335 From 34.0 grains to 36.0 grains 2225fps
    H-380 From 39.5 grains to 44.5 grains 2300fps
    H-414 From 40.5 grains to 45.0 grains 2290fps
    H-450 From 44.0 grains to 48.0 grains 2200fps
    H-4350 From 43.0 grains to 46.0 grains 2375fps
    H-4831 From 43.0 grains to 47.0 grains 2250fps
    H-4895 From 34.0 grains to 37.0 grains 2240fps

    H-380 and H414 were the best powders in my experence. Velocities listed were for highest load listed.

    a couple of other thoughts, from a 100yd zero and "standard" conditions, you will need 119 moa of elevation to get to 1760. Even if this is a dedicated 1000yd gun, you are looking at 76moa to get to 1760.
    A lot.
    In my opinion, the 220SMK is the best bullet to use if you were going to use the 308 win, at a mile, but there are some disadvantages to the reduced horsepower. Be ready for some very tapered bases. With a Ken Farrel 30moa tapered base, and Burris signature rings you have the option (with the interchangable ring inserts) of as little as 6moa taper, and as much as 54moa taper, all for around $100. That will get you in the ballpark if its a 1k gun-1mile gun you are after. of course theres always slr harbor for $1000...