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  1. #1
    Join Date
    Sep 2012
    Ft. Riley, KS

    Default 1:7.7 Twist Rate & Accuracy?

    So Iím thinking about picking up a new upper and Iím seeing 1:7.7 twist that claims to be really good for heavier 77gr bullets. It sounds great for those rare occasions I shoot a heavier grain but what about the 62gr I use standard? What about 55gr? Can anyone with experience with 1:7.7 twist barrels speak to their accuracy with 55 & 62gr bullets?

    "If you find yourself in a fair fight you failed to properly prepare..."

    "History is the autobiography of a madman..."

  2. #2
    Join Date
    Aug 2008
    Washington Co. Arkansas
    Never heard of 1-7.7; only 1-7 and 1-8. I've never had either of the later two have trouble with 55gr M193 or 55gr Hornady SP #2265. Never messed with anything over 68grs much though.

  3. #3
    Join Date
    Mar 2012
    There's more to accuracy than twist rate, so there's no real easy way to answer your question. Ultimately 1:7.7 is fine as is 1:8 for almost all bullets up to 80 grain. You will need to experiment with different bullets and rounds to see what your particular barrel prefers.
    "If you believe what you like in the gospels, and reject what you don't like, it is not the gospel you believe, but yourself." ó Augustine

    "That upon which you set your heart and put your trust is your god." ó Martin Luther

  4. #4
    Join Date
    Jan 2012
    NW Washington
    Don't worry too much about such an exact twist rate, that's more of a marketing thing to distinguish a particular manufacturer from everyone else's 1:7 and 1:8 barrels. Any of the above do fine with 50gr to 77gr bullets, if the barrel is good quality and the chamber was done right. There was (maybe still is) a similar trend in the 6.8 SPC crowd where some were convinced that 1:11.25 was the perfect twist, not 1:11, had to be 11.25. Small differences in twist rate are myopic details compared to just choosing quality gear and ammo and learning to shoot well.

    Of course with that said, if you're interested in accuracy, the common 55gr and 62gr FMJ are the poorest performers. (That's a function of the bulk FMJ construction, not the bullet weight.) Choose a quality bullet in the same or similar weight for better accuracy; there are so many good options that it would be misleading to point you to just one, just avoid FMJ.
    Last edited by Yondering; 10-30-2020 at 06:10 PM.

  5. #5
    Join Date
    Jul 2014
    I have rifles in 1-7 and 1-8 twist and both shoot the 77 gr Sierra bullets just fine, so I think a 1-7.7 would do just fine.

  6. #6
    Join Date
    Oct 2011
    In the good Old South
    Also...boat tail design enhances long range efficiency.

    "If your sport does not put grease, blood, or dirt under your fingernails, then it's just a game!"

  7. #7
    Join Date
    Jan 2005
    I have barrels in 1 in 7 twist and they shoot my M193 (55gr) up to 77gr razor core very well.

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