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Thread: 40-x rebuild

  1. #1
    Join Date
    Oct 2019
    Posts
    704

    40-x rebuild

    so the rifle came in and i inspected and fully dis-assembled.
    1982 rifle with OEM bbl...pretty tired.
    ordered a replacement from krieger....just over one week from order to delivery(this tues).
    ( an in stock bbl !) a number 9 is close to the original tho i will use 24-26" as a finished length.
    rebedded the action with pillars added. made new hex drive action screws.
    installed the timney HIT-ST, breaks nice at 12 oz.
    i need to look at bbl length/velocity with reloader 26. i can get 3000 fps with a 220 smk from 26.5"
    sit back and wait time.

  2. #2
    Join Date
    Oct 2019
    Posts
    704
    so.....long wait on a couple of items. i had the bbl nitrited. took a while, and decide on a folding stock.
    none fit the bbl dia, so went with a mcmillian front half and an ar back with a quality hinge in the middle.
    8.5-25x luepold scope in burris insert rings. 9" thunderbeast suppressor.

    the plan is to mimic the mk13 sniper rifle a bit. lilja mk13 bbl, reamer is navy mk13 reamer, bullets are 220 smk. quality available brass (NOS ABM..applied ballistics ammo line) win lr mag primer and 3.5 oal, and 2800-2850 in velocity with the 24" bbl of the later rifles. reloader 26 powder is a variation from h1000 but more vel/less pressure.

    initially nothing worked well. lots of 3 shot groups that were 2 and 1. started over and got some improvement.
    72.7 and 10 off shot .47 at 200 today. well under the 1moa spec of the mil rifle. ammo is in the 2825 ball park so perfect.
    so next up is to collect300/ 600/1000 yard zeros/accuracy. testing has been in front and rear rests, final proofing will be bipod and rear bag/support.

  3. #3
    Join Date
    Feb 2006
    Location
    Wild Nevada
    Posts
    600

    Question Caliber

    220 SMK at 2825 fps ,is this a 300 Win mag ?

  4. #4
    Join Date
    Oct 2019
    Posts
    704
    yes AND NO
    this is a mk248mod1.
    ammo designed for the mk13 sniper rifle.
    they started on 700 actions but went to stiller actions around mod 7.
    it has a higher operation pressure...68k plus vs std of 65
    it has a LONGER coal 3.5" vs 3.34 of oem
    you can look up the mil spec as mk 248 mod1
    reloader powder 26 makes it much easier to obtain the performance.
    mk13 is 26", ,mine is only 24 and i am still getting their performance.
    this is a single shot action.
    as with all reloading work up a safe load in your rifle.

    Quote Originally Posted by Worker View Post
    220 SMK at 2825 fps ,is this a 300 Win mag ?

  5. #5
    Join Date
    Oct 2019
    Posts
    704
    i have a nightforce 5.5-22x-50 coming that will replace the 8.5-25 luepold.
    both are 30mm tubes but the nightforce has 100 moa internal elevation....
    i can crank to the moon!

  6. #6
    Join Date
    Mar 2008
    Location
    Sun City, AZ
    Posts
    27

  7. #7
    Join Date
    Oct 2019
    Posts
    704
    have been waiting till fully complete...
    almost
    Quote Originally Posted by firearmsunlimit View Post

  8. #8
    Join Date
    Oct 2019
    Posts
    704

    pics

    black on black rifle...
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  9. #9
    Join Date
    Oct 2019
    Posts
    704
    so today was 600 yard zero.
    the prone guys were practicing and the let me set up a bench
    after pit duty. 2 fouling shots tracked well, then 5 target loads with
    started low but centered, finished in the x ring of a 300 yd f class target.
    ballistic software was off by 1.5 moa in elevation, windage stayed true.
    next up is to find a 1000 yard practice day

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