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Thread: fast twist 308

  1. #1
    Join Date
    Apr 2010
    Phoenix, Az
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    1 (100%)

    fast twist 308

    I recently read something on Snipershide or another type forum about fast twist 308s. That being like 1in8/1in9 barrels. I found it after watching the video from Snipershide Youtube channel where the guy was making hits at 1200 yards with a 20 inch 308.

    They were saying that the increased rotation increased range but I cant find the postings again and Im not finding anything else about it online.

    Is the range increased through less drag from the faster rotation or is the bullet more stable through the transonic range?

    Anyone have more to read/watch about this topic?
    C co 1/30th Infantry Regiment
    3rd Brigade 3rd Infantry Division
    OIF 1 and 3

    No dude is going to get shot in the chest at 300 yards and look down and say "What is that, a 3 MOA group?"

  2. #2
    Join Date
    Apr 2017
    Great lakes
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    I can only imagine fast twist bores doing well with long, usually heavy for bore, VLD bullets. Perhaps they were using 200 gr bullets. But, in a 308 enough muzzle velocity to stay supersonic to a 1200 m target will not happen. Perhaps they were engaging targets at high elevations where thinner air would allow a bullet to stay supersonic longer???

  3. #3
    Join Date
    Apr 2007
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    26 (100%)
    The fast twist helps with trans-sonic stability with the fat .30s.
    Still not as much of a gain as just going to 6.5 os something similar.
    Jack Leuba
    Director, Military and Government Sales
    Knight's Armament Company

    Director of Training

    FB@ Facebook.com/F2SConsultingLLC
    As accurate as needed, as fast as possible, as many times as it takes.

  4. #4
    Join Date
    Jun 2009
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    5 (100%)
    My 20 inch Remmy 700 with 5R (what is it 11.25) will go 1200 with 175’s.

    Tagging for interest mostly because I have never heard of this before. The one thing people might like trying to stretch their 308 since they already reload for it. Could be interesting for existing 308 horders like me.

    "Air Force / Policeman / Fireman / Man of God / Friend of mine / R.I.P. Steve Lamy"

  5. #5
    Join Date
    Jan 2010
    On top of a mountain, NC
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    10 (100%)
    I saw a video or two Frank put out on the topic a while back. Gain twist is another avenue to explore, along with left hand twist.

  6. #6
    Join Date
    Feb 2009
    Western KY
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    43 (100%)
    while 1,200y/m can be done with a .308, it kinda sucks. On a windy day, or if you're needing to actually kill something at that distance... just sayin'

  7. #7
    Join Date
    Sep 2007
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    14 (100%)
    I shoot 175 SMKs out of my 20" 1/12 to 1300 yards at our spot. The only reason I'd want a 1/9 is if I wanted to shoot a REALLY long bullet.
    "You people have too much time on your hands." - scottryan

  8. #8
    Join Date
    Oct 2006
    College Station, Texas
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    6 (100%)
    Velocity decay for an individual 175 to 208-grain bullet out of a 16- to 20-inch barrel is going to be the same regardless of the twist.

    The theory is if the projo is still spinning fast through trans-sonic it will remain point-forward and not start a precessing "Wobble" around its axis (making your group fatter with more random impacts than point-of-aim). Start with a 14.5 or 16-inch barrel and your muzzle velocity is already 100-150~200 fps slower than a 20-incher.

    Faster twist is also going to give you more drift in the direction of rifling, especially at the longest ranges and as velocity decays past trans-sonic.

    No free lunch -- you want the bullet to do work, the more changes you add the more variables you add.

    It's really critical that you start with a very good barrel. Palma shooters used to use 28- to 30-inch .298" tight-bore slow-twist barrels to get the most velocity out of 155-grain bullets to hit 1000, 1100, and 1200-yard bullseye targets with single-shot bolt-action rifles. Those light bullets don't have the same wind-bucking inertia of heavies (175 to 208-210s).


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