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40 gr VMAX bullet in 1/7 barrel?

Discussion in 'Black Rifle Forum' started by Dizzy Beaver, May 16, 2013.

  1. Dizzy Beaver

    Dizzy Beaver

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    I picked up some Hornady 40gr VMAX ammo by mistake (didn't pay attention to the box when I bought it). Will this work in a 1/7 barrel? I've read that a bullet with a thin jacket may fall apart in flight because the jacket gets torn in barrels with a high twist rate. Just wondering if I use this for varmints on a friend's farm if this is going to be an issue.

    Thanks!
     
  2. JimBianchi

    JimBianchi Da Da CLM

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    I tried a box in my 1/7 20in FN barrel and they grouped so badly I thought I broke the scope.

    Tried the 69gn match and it was still dead on, so it was ammo related.

    Groups were so big and disjointed at 50m I thought I might hit myself.....

    (Glad I only bought one box!)
     

  3. faawrenchbndr

    faawrenchbndr CLM

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    A 1:7 barrel is not going to stabilize those 40gr bullets
     
  4. fuzzy03cls

    fuzzy03cls

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    You should be able to hit a target at 50 yards. After that it will open up.
    I have some of this ammo & shot it recently because of the shortages & I wanted to test a new upper out. 14.5" 1/7.
     
  5. Dizzy Beaver

    Dizzy Beaver

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    Dang. What about 50 grain bullets? I have a couple boxes of 50 grain fiocchi extrema 50 grain vmax too.
     
  6. Gunnut 45/454

    Gunnut 45/454

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    Dizzy Beaver
    The 50 gr bullet should shoot fairly well - I've shot 50 gr SEI's and they were not great for accuracy but useable!:supergrin:
     
  7. faawrenchbndr

    faawrenchbndr CLM

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    I'd say with the 40 or 50 grain bullets, you should be ok at 25m.
    May be able to get a 3" grouping, 50m would be pushing it, may get a 6-8" grouping
     
    Last edited: May 17, 2013
  8. bmoore

    bmoore

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    Word. 40grn VMAX is a hot round.
     
    Last edited: May 17, 2013
  9. dkf

    dkf

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    A 50gr is about as light as a 1:7 could stabilize but that may depend on the barrel.

    It won't hurt anything to shoot some and try them out. You can tell if the bullets are tumbling by inaccuracy and the bullet hitting the target sideways.
     
  10. Roostmonkey

    Roostmonkey

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    My LE6920 doesn't even like 55 grain bullets much. I would trust it to make a hit on a a man-sized silhouette at 100m, but that's about it. 62 grain penetrators are about 3 moa. YMMV.
     
  11. WoodenPlank

    WoodenPlank Who?

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    Shoot it and see.

    Also, don't get hung up entirely on bullet weight. Bullet LENGTH is what relates to barrel twist. While length and weight will scale with similar bullet construction, different types of bullet may behave differently. A 50 grain Barnes TSX will be longer than a 50 grain V-MAX, for example.
     
  12. Gunnut 45/454

    Gunnut 45/454

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    I would also suggest slowing them down, run them at about 3000 fps instead of 3800! This will stop the over rotation of the bullet in the 1:7" twist!
     
  13. WoodenPlank

    WoodenPlank Who?

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    Yep, that's another way to do it.
     
  14. marvin

    marvin sci-fi nut

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    you'll be fine. don't worry about over rotation, i know a guy that use's 40 grain BT out of his colt all the time and it kills ground hogs out to 300 yards. what more do you need
     
  15. bmoore

    bmoore

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    My uncles friend at work has a friend who's sister knows a guy that knows a guy who kills mice with is his Colt 6920 at 800 Meters.
     
  16. deerhunter34

    deerhunter34

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    Sounds like it is plenty safe to shoot them, but you are going to have to ask your rifle whether it can do it accurately.
     
  17. Dizzy Beaver

    Dizzy Beaver

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    I should have no problem then. I prefer to just shoot the tails off the mice using iron sights at 300 yards, so it sounds like they'll be plenty accurate for that. :rofl:
     
  18. Matthew Courtney

    Matthew Courtney Instructor #298

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    Shorter 1/7 barrels shoot 40gr bullets better because lower muzzle velocity means lower rpm's. 20 inch barrels do not often work with 40gr vmax, but many 14.5 and 16 inch barrels may. My 6920 shoots them well, but my match sporter does not.
     
  19. eccho

    eccho

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    :rofl::rofl::rofl::rofl:
     
  20. marvin

    marvin sci-fi nut

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    over stabilizing use to be a big deal years ago when most bullets weren't balanced near as good as today's bullets. if you shot some with to much twist the bullets could wobble in flight an accuracy would go to hell and you could over stress the bullet till it fails in flight

    now with the new v-max's and nosler BT's they are so well balanced that the only thing to worry about if the bullet breaking up, but even that is less likely to happen now days because they make the base's stronger than they use to.

    the only other thing that might come up is i've read that a bullet that is over stabilized tends to ride nose up out past 600 or 700 yards
     
    Last edited: May 19, 2013