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Ammo help

Slimpicken5
I just bought a new scope and ammo for my 270. When i went to sight my rifle, my ammo (270 winchester super x) was actually 30-06 ammo. I checked the box again and the box was 270 how could this happen? Also what would have happened if i tryed to shoot this? Thanks David
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Comments

13 comments

Date Votes
  • Slimpicken5
    Hello,

    So is the 5.45x39 a .308?
    what does the 7.62x51 match up with?
    also what about the 7.62x54 does it match up with any other caliber??

    Thanks for the answers.

    Slim
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  • Mobuck
    Any 223 Remington ammo will fit an AR in 5.56 or 223. All 223 ammo uses a .224 diameter bullet. Some type/weight bullets will be more accurate or function better than others but generally, any 223 ammo within manufacturers specifications will fire and function in a properly assembled AR type rifle. Personally, I prefer to use ammo with bullets crimped to prevent the bullets being pushed back into the case during the magazine to chamber transition. This is due to a bad experience resulting from such an occurance some time back.
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  • carbine100
    Bullet weights are listed in grains.
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  • v35
    The term .223 is a misnomer for the AR15. Bullet weights from 35 grains to about 80 grains and .224 " in diameter can be used.
    In order to use heavier bullets a faster rifling twist is needed. One turn in eight or nine inches works for low to medium weights and one turn in seven for heavy weights.
    Powder and bullet weights are expressed in grains where one grain equals one seven thousandth of a pound.
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  • Slimpicken5
    Thank you for the info.

    I was looking at some 60Gr .224 would that classify as "heavy"
    My AR has the 16" barrel and isaChromeMoly Steel Barrel But i have no idea of how many twists, i thought something like 1x9 twists?? if that makes sense. i guess it would mean 1 twist every 9 inches.
    anyways wasnt sure if this ammo would do extra dmg or not.?
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  • 11b6r
    Here's how to determine "rate of twist"-
    1. Make sure rifle is UNLOADED
    2. Then do it again!
    3. Find a cleaning rod where the rod feely swivels on the handle.
    4. Fit the snuggest fitting patch to the rod you can.
    5. Insert patch/rod into the bore. Push to the end of the bore.
    6. Attach a masking tape "flag" to the rod at the muzzle, leaving a tab sticking up.
    7. Hold weapon so flag is straight up, at the 12 o'clock position.
    8. Gently withdraw rod, allowing it to turn with the rifling. Notice the flag is turning?
    9. When the flag rotates back to the 12 o'clock position, STOP. Mark the rod at the muzzle- another bit of tape, sharpie marker, teeth marks, etc.
    10. Now measure distance in between your start and end marks. That is the rate of twist- 1 turn in 6 inches, 14 ", 64" etc.

    Wroks for just about anything with a snug patch (maybe a drop of oil) EXCEPT early Colt revolvers, Carcano rifles, and maybe others- they had 'Gain Twist" rifling- rate of twist increased as you go up the bore.
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  • partisan
    The rate of twist on the AR-15 is usually 1:7 or 1:9 . The rate of twist determines which bullet weight works best for your rifle.
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  • Slimpicken5
    So I am guessing that the 55gr and 62gr .223 rounds are just fine for a Bushmaster AR-15 16" barrel. Which i think has the 1X9 but not positive(I do not have the gun in my hands yet) so it could be the 1x7.

    Thanks again
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  • beantownshootah
    The "standard" .223 round was (for years) 55 grain, and most ammo is either 55 or 62 grain. Either a 1:7 or 1:9 twist should stabilize either of those two rounds.

    As already mentioned, the heavier the bullet, the FASTER the twist you need to stabilize it.

    Assuming the ammo itself is safe, firing a heavy bullet through a slow twist barrel won't hurt the gun, but it will understabilize the bullet, leading to poor accuracy, and can (in the worst case) cause bullet tumbling, which not only leads to lousy accuracy, but also greatly reduces range and terminal ballistics.

    What has NOT been mentioned is that it actually is possible to "overstabilize" a light bullet with two fast a twist rate, also leading to less than maximum accuracy. Too fast a twist combined with super light bullets can actually cause the bullets to disintegrate, though again, in practice, this probably won't ever be an issue for most shooters.

    Apart from actually measuring it, one fairly easy way to determine the twist on your particular gun is to consult the manufacturer.

    And as a quick rule of thumb, if you intend on shooting mostly factory standard military-type ammo a 1:9 twist rate is probably best. Your Bushmaster probably does have the 1:9 twist rate.

    If you intend to shoot primarily varmints with LIGHT bullets, you want a slower twist.

    Conversely if you intend to use heavier bullets (eg for long range target shooting, or hunting bigger animals), then you want a faster twist.
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  • partisan
    Slim- You are correct. Either bullet will be just fine. When you start worring over 55 gr. & 62 gr, it really doesn't matter that much, except for very long range shooting. Get the one that is cheaper, and enjoy shooting it!
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  • Slimpicken5
    All i am doing is target shooting , some long range but all for fun. Very little varmit hunting.

    I have been looking to buy the wolf 55gr .223 rounds which seem to be the cheapest BUT I was talked out of Wolf because of the steel and into a brass like federal, he was saying the steel is a much worse round and can possibley expand so bad it could do barrel damage. He did't say how often 1/1000 1/10000??, only problem with the federal brass ammo is it's 4 dollars more a box.(i buy in bulk so that adds up) Also he said that the 5.56 and .223 are 2 different rounds and the 5.56 will work better in my bushmaster??

    Any info or correction on this?

    Thanks a million,

    Slim
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  • partisan
    There is no difference in the 5.56 and the .223. Wolf is the cheapest partly because is dirtier than the better stuff. I have never shot Wolf in my Ar-15, but would if I had some. I would make Wolf the last brand I would buy, but I doubt it would do any damage to your barrel. This is about all I know of Wolf ammo, so maybe one of the shooters out there that use it will be able to tell you more. Just remember, Slim, 5.56, .223, 55grain, 62grain, are basically all the same, unless you are a sniper and/or doing really long range varmit shooting! Hope this helps a little.
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  • nononsense
    Slimpicken5,

    I'm adding some information to this topic because there have been some misleading statements made and I don't want this forum to suffer because of them. All of your questions are good, basic 'need to know' type questions so getting the right information is important.

    There are two cartridges that are very similar but slightly and importantly different from each other:

    .223 Remington

    5.56 x 45 NATO

    The outside case dimensions are the same for both cartridges. The inside dimensions of the cases are different with the military cases having slightly thicker walls. The primary difference between the two cartridges is the length of the leade and the angle of the throat and this relates to pressure.

    223vs5.56SAAMI.gif

    From SAAMI:

    "With the appearance of full metal jacket military 5.56 ammunition on the commercial Market, it has come to the attention of the Sporting Arms and Ammunition Manufacturers' Institute (SAAMI) that the use of military 5.56mm ammunition in sporting rifles chambered for Caliber .223 Remington cartridges can lead to higher-than-normal chamber pressures and possible hazards for the firearm, its user and bystanders.

    tests have confirmed that chamber pressures in a sporting rifle may be significantly higher in the same gun when using military 5.56mm ammunition rather than commercially loaded Caliber .223 Remington cartridges, according to SAAMI.

    SAAMI points out that chambers for military rifles have a different throat configuration than chambers for sporting firearms which, together with the full metal jacket of the military projectile, may account for the higher pressures which result when military ammunition is fired in a sporting chamber.

    SAAMI recommends that a firearm be fired only with the cartridge for which it is specifically chambered by the manufacturer."
    http://www.thegunzone.com/556v223.html

    This article and others listed along the right side in another menu, explain the development of both cartridges and use a timeline to keep the facts straight:

    http://www.thegunzone.com/556faq.html

    Generally, rifles are marked for the specific cartridge or chamber, especially where the AR family of rifles is concerned. Since the ammunition isn't precisely interchangeable, it's important to stay with the specifics as marked until you develop a better understanding of the differences.

    Twist rate is based on the LENGTH of a bullet not the weight. This is unfortunate since most bullet makers don't tell you the length of each bullet upfront. However, some are starting to print the recommended twist rate on the box. Generally though the heavier bullets are longer than lighter bullets and require a faster twist. The exceptions for the very fast twist rates go along with the specialty bullet designs.

    The Greenfield formula is the basis for development of the concept for twist rate and stability:

    The formula is T=150(d/r) for velocities from about 1500 to 2800 fps. Substitute 180 for the 150 value for velocities exceeding 2800 fps. "T" is the twist rate. "d" is the bullet diameter. "r" is the bullet length to diameter ratio (length of bullet divided by diameter).

    Spitzer_vs_Roundnose.jpg

    These two bullets are the same caliber and weight but have very different lengths which require different twist rates. Guidelines for twist rates can be found on most barrel makes websites. This is one example:

    .224 CF
    - 7" for bullets heavier than 80gr.
    - 8" for bullets up to 80gr.
    - 8"* Ratchet rifled 4 groove
    - 9" for bullets up to 70gr.
    - 12: for bullets up to 63gr.
    - 14" for bullets up to 55gr.
    - 14"* Ratchet rifled 4 groove
    - 15"* for bullets up to 55gr. driven 4,100 pfs or more
    - 16:* for bullets up to 55gr. driven 4,300 fps or more

    The rule of thumb for twist rate and accuracy is that we should use the slowest twist rate that will stabilize that particular bullet length. This will generally yield the highest degree of accuracy.

    The faster twist will exacerbate or magnify any flaws that exist in the bullet as manufactured, creating inaccuracy.

    I suggest doing a search for articles about twist rate and see if that raises more questions. Post again when you want a little more explanation.

    Best.
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