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Author Topic: 175 SMK vs. 155 SMK Palma  (Read 2580 times)

StevenTing

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175 SMK vs. 155 SMK Palma
« on: July 15, 2014, 05:42:20 pm »
Anyone reload for their 308? I'm currently using 175 SMK but am looking to try 155 SMK Palma for distance.  I can push the 155's faster and based on Shooter, They won't go transonic until about 1360 yards.  The 175's go transonic at 1440.  The BC's are fairly close and I just wonder about pushing the lighter bullet, faster.  There is about a 2 grain difference in powder but not sure how that translates to recoil.
Utah

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    Nick Cage

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    Re: 175 SMK vs. 155 SMK Palma
    « Reply #1 on: July 21, 2014, 12:59:03 pm »
    I load .308 and I roll 175s almost exclusively.
    The 155 Palma needs a different twist to stabilize properly as I understand, I believe it needs to be a tighter twist than most .308 barrels are, something like 1-10. I believe the 155 Palma stabilizes like a much heavier bullet.
    I picked up a box of 155 Palmas a while back haven't had the opportunity to put them through their paces yet.

    StevenTing

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    Re: 175 SMK vs. 155 SMK Palma
    « Reply #2 on: July 21, 2014, 05:32:34 pm »
    Hmm.. I always thought the heavier the bullet, the tighter the twist.  I think most plinking 308 ammo are 150 grains.  I have a 1:12 twist and I'm currently shooting 175's but I think I'm pushing it there.  the Palma's have a similar BC and I thought it might be better with the 1:12.

    However, since I'm shooting a 20 inch barrel, I may not get enough velocity to see the benefits of the 155 over the 175's.
    Utah

    Nick Cage

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    Re: 175 SMK vs. 155 SMK Palma
    « Reply #3 on: July 22, 2014, 03:25:32 pm »
    It usually is the heavier the bullet the tighter the twist. The palma projectiles are shaped differently, they have a longer ogive than the old 155s and in general shoot like a heavier bullet (see pic) so they need a tighter twist even than 175s.



    FWIW I haven't seen much difference in recoil, but I've only shot a few rounds and I'm not exactly recoil sensitive anyway.

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