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.223: 55 gr bullets in fast twist?

redpeteredpete Member Posts: 154 ✭✭✭
edited June 2015 in Ask the Experts
I know that a faster twist barrel in a .223 should shoot heavier bullets, but will a 1:8 still shoot 55 grain bulk bullets OK?


  • charliemeyer007charliemeyer007 Member Posts: 7,346 ✭✭✭
    edited November -1
    It should, but you might suffer accuracy loss due to a long throat. The real answer is to shoot some and see.

    added I'm guessing the barrel is shot out. Will it shoot heavier bullets in some sort of normal group? A bad crown, crooked muzzle break might cause tumbling, but a really eroded throat and worn rifling are my bet.

    added 2: I have a shot out 256 Newton barrel and yes bullets would keyhole at 10 yards.
  • nononsensenononsense Member Posts: 10,934 ✭✭✭✭
    edited November -1

    The rule of thumb for best accuracy is to use the slowest twist rate which will stabilize the bullet length.

    Because we are all-around shooters and not benchrest shooters only, we have to make some compromises. Sometimes we want to shoot lighter, shorter bullets in fast twist barrels but there are requirements.

    The chamber must be straight and be concentric with the bore. In essence the bullet has to enter the throat and bore straight. If it's tipped even slightly your accuracy will suffer. This also means your ammunition has to be straight.

    But here's a slight kicker. Bulk bullets can be excellent quality or they can be questionable. If the quality is questionable they might have trouble with the faster twist. This usually stems from the core of lead not being concentric with the copper jacket so it doesn't spin around it's axis at the higher rate of twist. Faster twist rates will magnify any errors in bullet making leading to poor accuracy.

    As stated it's always better to try some and do your best work when assembling the cartridges.

  • Okie743Okie743 Member Posts: 2,224 ✭✭✭
    edited November -1
    It will shoot'em ok, but they may not all go the same direction.

    If you mean shoot a good group you will need to reload for max accuracy during a test. You can get a general idea using factory ammo and if 2 inchs or less at 100 yard you stand a chance that reloading may help reduce the group.

    What is the model of the gun?
    What kind of group do you call ok?
    or do you just mean shoot em out the end of the barrel?

    I reload bulk 223 bullets for general playing around practice in some very accurate 223's and usually see the groups open up by an average of about 1 1/2 inchs at 100 yards probably mainly due to imbalance in the bullet. (balance not coincentric)
  • redpeteredpete Member Posts: 154 ✭✭✭
    edited November -1
    The bullets are tumbling coming out of this gun. The loads work fine in other AR's so I think the issue is either with the barrel or the muzzle break. The bullets are going thru the target sideways at 10 yards.
  • jonkjonk Member Posts: 10,121
    edited November -1
    Sometimes you just don't know. I have a 1:7 twist Savage 12 that should do best with 69 and 73 gr bullets. What's it's favorite? Hornady 50 gr Vmax over 26 gr of BLC2. Will shoot a 1.5" group at 300 yards.

    I think in that case, some of the issue is that the polymer tip essentially makes it a longer bullet with a different center of gravity than it would normally have at that weight; because it isn't entirely the WEIGHT that's at issue, so much as the profile and length.

    It will however also shoot regular 55gr FMJs sub MOA. 45 gr bullets fly apart from the centripetal forces.

    So load 'em up and see!
  • dcs shootersdcs shooters Member Posts: 10,969
    edited November -1
    quote:Originally posted by redpete
    The bullets are tumbling coming out of this gun. The loads work fine in other AR's so I think the issue is either with the barrel or the muzzle break. The bullets are going thru the target sideways at 10 yards.

    At ten yds they are not stabilized, which is normal.
    Try at 100 and see if the hole is round [^]
  • MG1890MG1890 Member Posts: 4,649
    edited November -1
    It should shoot 55's just fine. If it don't, it ain't the twist rate causing it.
  • MobuckMobuck Member Posts: 12,967 ✭✭✭✭
    edited November -1
    "It should shoot 55's just fine. If it don't, it ain't the twist rate causing it."
    Good response. Is it every bullet keyholing? Even a smooth bore won't keyhole @ 10 yards. You've got a problem with your muzzle-either a seriously damaged crown or bullet striking muzzle device.
    Some of my AR's have 1-8 twist and I don't see any problem with them shooting bullets down to 40 grain Ballistic Tips(I don't have any lighter than that).
  • Laredo LeftyLaredo Lefty Member Posts: 13,452 ✭✭✭
    edited November -1
    Remove the muzzle break and see if they are still tumbling at 10 yds.
    If they don't then your MB is the problem. If they tumble without the break, then re-barrel the gun.
  • v35v35 Member Posts: 13,200
    edited November -1
    The last three replies are spot on.
    55 gr bullets shoot well in 1:7 twist.
    The 1 in 8 twist is supposed to be the best compromise for 55-70.
    Are the bullets pulled military or new?
    I bought and returned pulled 22-55gr mil bullets that weren't round.
    However pulled 30-150 gr pulled bullets shoot fine.
    Pull the brake, measure the bullets.
    Before you chuck the barrel, verify the bullets aren't bad.
  • Okie743Okie743 Member Posts: 2,224 ✭✭✭
    edited November -1
    Does it group any bullets or loads?

    If others are not grouping after you have removed the brake, try copper foul cleaning of the barrel. I've had copper fouled barrels completely, erratically loses bullets, don't know where they went when they come out the end of the barrel and removing the copper fouling corrected such.
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