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What .223 bullet weight is best for 1:9 rate of twist

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  • LinefinderLinefinder Posts: 7,856 Senior Member
    Linefinder wrote: »
    Though I use a 12 twist now, my first .223 was a 9 twist. Shot well with everything I ever fed it, including 40 grainers.
    I'd say you're good for pretty much anything you're liable to want to shoot in it.

    Mike

    That was my story a year ago, and I'm sticking to it. I don't like to over-think things. Some would say I take that to an extreme. :tooth:

    Mike
    "Walking away seems to be a lost art form."
    N454casull
  • Ernie BishopErnie Bishop Posts: 8,609 Senior Member
    In the end, if you think bullet stability is marginal, just try it in your rifle. A couple at 100 yards, then more at the max distance you would shoot.
    Any questions will be answered on the paper and or maybe off of it:jester:
    Ernie

    "The Un-Tactical"
  • LinefinderLinefinder Posts: 7,856 Senior Member
    Any questions will be answered on the paper and or maybe off of it:jester:

    You're pretty eloquent, considering you're in Wyoming and all.

    Mike
    "Walking away seems to be a lost art form."
    N454casull
  • PegasusPegasus Posts: 2,874 Senior Member
    Linefinder wrote: »
    You're pretty eloquent, considering you're in Wyoming and all.

    Mike

    You have no idea. :grin:

    Actually Ernie is a very interesting guy with whom to talk.
  • Ernie BishopErnie Bishop Posts: 8,609 Senior Member
    Linefinder wrote: »
    You're pretty eloquent, considering you're in Wyoming and all.

    Mike
    I am very Egi-cay-ted :)
    Ernie

    "The Un-Tactical"
  • centermass556centermass556 Posts: 3,618 Senior Member
    Pegasus wrote: »
    I have a simple question for you; does a 1:9 twist stabilize the M855 62gr ball ammo?


    Yes it will, but that is not the Argument. The argument is why the Army went to 1/7. They went to 1/7 for the M855, steel Core Full copper jacket round. 1/14 would have done for the 55gr round, but the users at the tip wanted the 1/12....1/9 will stabilize a M856, just as 1/10 will work for the M855. I have no idea why they went so "tight" for the M855, but they did...it was not for the purpose of the M856...and it wasn't for Arctic conditions...
    "To have really lived, you must have almost died. To those who have fought for it, freedom has a flavor the protected will never know."
  • Big ChiefBig Chief Posts: 32,995 Senior Member
    Sarge, were you concerned about the right twist rate/bullet weight/ profile when you squeezed the trigger on your M-4 or cut loose with a SAW burning up 200 rounds from a box magazine while engaging members of that that religion of peace and goodwill toward mankind, I think not! :guns::guns::guns::guns:

    I see a lot of misconceptions/not exactly correct statements too on the Hitler Channel/Military Channel and know better from personal experience and real life observations.

    My understanding when they issued us M16A2s to replace the M16A1s (back in the mid 90s) was the twist rate was changed to better stabilize the heavier 62 grain projectile they wanted to use. I think the idy was to up the bullet weight and gain more penetration/lethality/longer range effectiveness without having to go to another caliber and be standard with NATO using a rifle that would in a pinch feed and fire the old and new 5.56 ammo.

    Take care and don't eat no Yeller Snow :tooth:

    PM sent.
    It's only true if it's on this forum where opinions are facts and facts are opinions
    Words of wisdom from Big Chief: Flush twice, it's a long way to the Mess Hall
    I'd rather have my sister work in a whorehouse than own another Taurus!
  • PegasusPegasus Posts: 2,874 Senior Member
    I seriously doubt a 1:9 twist will stabilize a 1.15 inch bullet. I have never shot M856 but I have used a lot of bullets that are almost as long or longer and they do not stabilize in 1:9, which is why the 1:8 twist is very popular in match rifles in which we shoot the 80 and 82gr bullets to 1000 yards.
  • centermass556centermass556 Posts: 3,618 Senior Member
    Wait...So you are saying you are arguing about something you have no first hand knowledge about!!! I don't know if you have realized this, but not everything you read in a book is correct. Things behave differently in the real world with real world application....I have done it. I know for a fact 1:9 will Shoot a tracer, because I have done that too...The M&P 15 has a twist rate of 1:9.

    I have also been taught pratical application Military rifles by some the best SMEs in the world. The guys that have been around the block once or twice. Guys that have been on the PM team for weapons design and procurement. Everything I know about the M16/M4 series rifles for the military either came from first hand knowledge or from the guys that had "say so" in development. Not some book, magazine, or hour program on cable.

    Keep your nose in the books, when you get ready for real word application of hot lead and weapon design let me know. Class Dismissed.
    "To have really lived, you must have almost died. To those who have fought for it, freedom has a flavor the protected will never know."
  • PegasusPegasus Posts: 2,874 Senior Member
    There are some things one doesn’t need to try to know the result will not be good. For instance, I have not mashed my hand with a hammer because I know it’s not going to be good. When it comes to ballistics, there really is nothing new under the sun because most of it has been well understood for a long time now. What is fairly new-ish are calculators and apps that you can use to figure things out pretty close to reality. Of course, the output of these apps is only as good as the input, but if you do the job properly, you can get information that is really good.

    As an example, this past weekend I shot a medium range F-class match with my F-TR rifle and LR ammo. That rifle is zeroed at 1000 yards and the most changes I’ve tried was 800 yards and 900 yards at the recently concluded F-Class World Championship. I used the output of JBM to get close at 800 and 900 and used the practice day in Raton to refine those zeros. JBM put me in the black, I got to the X ring with just a few more adjustments. So last Sunday, I did the same. Under my local conditions, JBM told me to come down 16.1 MOA from 1000 yards. That put me in the black at 600 and I got to the X with a few more clicks.

    These calculators help the cognoscenti accomplish what they want with a minimum of component usage and we can quickly eliminate things that are not possible or just plain bad. This is not to say that these calculators are the final word; you still need to verify confirm these numbers with your rifle and ammo.

    One of the JBM calculators is something called “Stability.” This application, given bullet caliber, weight and length along with muzzle velocity, barrel twist, temperature and pressure will produce a stability number, called the Miller stability value. If the number is above 1.3, you know your bullet will be statically stable. Between 1.0 and 1.3, you should be fine, but it’s on the edge and temperature may affect the results. Anything below 1.0 is unstable and you don’t even want to try it unless you like to see strange stuff. The application does have a special note that the military uses 1.5 as the minimum.

    A lot of people use these types of calculators to pick a twist rate for their precision rifles because as I explained before you always want t use the minimum twist rate needed to properly stabilize the longest bullet you would ever use in that barrel.

    The M856 fires a bullet that weighs 63.7 grains and measures 1.15 inch at a velocity of 2800FPS in a 16inch barrel. I used 59 degrees F and 29.92 in Hg, (STP).
    At 1:9, the stability factor is 0.750, highly unstable.
    At 1:8, the stability factor is .95, somewhat unstable.
    At 1:7, the stability factor is 1.240, stable.

    So, excuse me if I don’t believe that you can stabilize the M856 in a 1:9 twist.

    Now, let’s have a look at the M855; length 0.91, weight 62gr, MV 3200FPS
    At 1:12, the stability factor is 0.848, unstable.
    At 1:10, the stability factor is 1.22, stable.
    At 1:9, the stability factor is 1.5, highly stable.
    At 1:8, the stability factor is 1.91, even more stable.
    At 1:7, the stability factor is 2.50, so stable it will not wobble going through targets.


    Just for grins, I ran the numbers for the M193 bullet; length 0.75, weight 55, MV 3300.

    At 1:14, the stability factor is 0.971, slightly unstable.
    At 1:12, the stability factor is 1.322, very stable.

    Just for grins, I changed the temperature to -40F and the 1:14 twist is 0.79, highly unstable, whereas 1:12 twist is 1.069 barely stable.

    Now, you’re perfectly free to disbelieve all of the above or just ignore these calculators, I don’t really care one way or the other, but I use these calculators to help me design my world-class match loads and I have great success with them.
  • Randy CRandy C Posts: 36 Member
    :cool2: I think :fan: :deadhorse:
  • centermass556centermass556 Posts: 3,618 Senior Member
    Until you do it in real life....in practical application, your argument is invalid. NASA has learned painfully that Chalkboard work, no matter how mathematically correct the answer is, does not always hold true in the real world. What you believe and don't believe is based on faith. Faith in someone else's work or deed. You just created a new religion from your armchair ballistics belief in a weapon system you have no practical knowledge of. That in itself is a major accomplishment. I guess arrogance will get you somewhere...

    The Army went to the 1:7 twist specificly for the M855, SS109 round of steel core and copper jacket developed by the Belgiques.

    Until you travel the world, with practical application of your trade...it is not world class. It is just something fancy you do with your calculator and rifle for amusment....
    "To have really lived, you must have almost died. To those who have fought for it, freedom has a flavor the protected will never know."
  • PegasusPegasus Posts: 2,874 Senior Member
    Until you do it in real life....in practical application, your argument is invalid. NASA has learned painfully that Chalkboard work, no matter how mathematically correct the answer is, does not always hold true in the real world. What you believe and don't believe is based on faith. Faith in someone else's work or deed. You just created a new religion from your armchair ballistics belief in a weapon system you have no practical knowledge of. That in itself is a major accomplishment. I guess arrogance will get you somewhere...

    The Army went to the 1:7 twist specificly for the M855, SS109 round of steel core and copper jacket developed by the Belgiques.

    Until you travel the world, with practical application of your trade...it is not world class. It is just something fancy you do with your calculator and rifle for amusment....


    The SS109/M855 does NOT have a steel core, it has a lead core with a 10gr steel penetrator at the tip. Where DO you get your information?


    I did not have to travel the world; I guess you were not paying attention earlier, but the world came to me, or rather close enough to me that I was able to go meet it. Last month, I competed in the F-Class National Championship (FCNC) followed right after by the F-Class World Championship (FCWC), in Raton, NM. There were 14 countries represented there and I can assure you that it was not their worst shooters that travelled multiple thousands of miles to compete. The FCNC was divided into 2 parts, the individual portion and the team portion. The individual portion was shot over three days with day one and day 2 being 3 strings of 15 shots at 1000 yards and day 3 being 2 strings of 20 shots at 1000 yards.

    I placed 22nd overall for the FCNC and on day 3, I placed 7th overall shooting a 199-7X out of a possible 200 in the first match. I would say that my ammo is "world-class." I would even say my rifle is "world-class." I might even think of myself as a "world-class shooter," but since my humility is second to none, I attribute my success to my world-class ammo and world-class rifle and world-class luck. I had more difficulty in the FCWC matches but I placed 43rd overall shooting about the same percentage (96%) as in the FCNC. The FCWC individual portion was two days with [email protected], [email protected] and [email protected] each day with an extra 5 rounds at 1000 on the last day.

    This is a civilian board, and this is what civilians do; some hunt, some plink, some shoot targets and some compete in world class matches.
  • ZeeZee Posts: 28,411 Senior Member
    image-41.jpg
    "To Hell with efficiency, it's performance we want!" - Elmer Keith
  • breamfisherbreamfisher Posts: 14,104 Senior Member
    Really? Deepak Chopra? REALLY?!?!?
    Meh.
  • ZeeZee Posts: 28,411 Senior Member
    Really? Deepak Chopra? REALLY?!?!?

    I've no idea who that guy is.

    But, I guess I could have posted this for Peg instead.

    image-42.jpg

    :-)
    "To Hell with efficiency, it's performance we want!" - Elmer Keith
  • breamfisherbreamfisher Posts: 14,104 Senior Member
    Chopra's an alternative/holistic/transcendental meditation medication advocate.
    Meh.
  • ZeeZee Posts: 28,411 Senior Member
    Oh well.
    "To Hell with efficiency, it's performance we want!" - Elmer Keith
  • Big ChiefBig Chief Posts: 32,995 Senior Member
    Chopra's an alternative/holistic/transcendental meditation medication advocate.

    Thanx, I wuz wondering who that esoteric writer was. Leave it to Zee to come up with stuff/quotes from the edges of the realm.

    Then again who am I to talk, we all have our own little idiosyncrasies.

    I often post Bob Dylan lyrics ' ............And if my thought dreams could be seen, they would probably put my head in a guillotine.....it's alright Ma, I'm only sighing....'
    It's only true if it's on this forum where opinions are facts and facts are opinions
    Words of wisdom from Big Chief: Flush twice, it's a long way to the Mess Hall
    I'd rather have my sister work in a whorehouse than own another Taurus!
  • ZeeZee Posts: 28,411 Senior Member
    I just figured such an epic high dive into the ego pool as Pegasus made required a deep thought for safety.

    :-)
    "To Hell with efficiency, it's performance we want!" - Elmer Keith
  • centermass556centermass556 Posts: 3,618 Senior Member
    Seriously, you don't know this? It isn't on one of you calculators or in a book....the original ss109, m855 round that Belgium designed and caused the American army to choose a 1:7 twist in the A2 version of the M16 had a steel core.... The original steel core design of the SS109 was what spurred the design of the M855A1 with an exposed steel tip penetrator that is surrounded by copper...

    the army adopted the 1:7 rifle twist for the Belgium designed SS109, M855 steel core copper jacketed 62gr round...



    Sent from my iPhone using Tapatalk - now Free
    "To have really lived, you must have almost died. To those who have fought for it, freedom has a flavor the protected will never know."
  • 5280 shooter II5280 shooter II Posts: 3,923 Senior Member
    Ok boys, back into your corners and get back to the OP's question.......(time out for Center and Peg). My ARs are 1:8 and 1:9........they shoot everything I can get my hands on with boring accuracy.......but it seems the magic weight is the elusive 64 grain for cheap plinking. Really haven't gone heavier cause I have no need, I don't hunt game with that caliber.

    To entertain the military argument..........remember the .223 was competing against the 7.62 and had to penetrate a steel helmet at excessive yardage. It required a stronger bullet and thus the SS109 was created. (Yay freaky-deaky Dutch and Belgian Waffles!)

    In the initial testing of the M-16.........Artic testing at Ft. Greeley did show destablilization of the 55 gr bullet at stupid low temps and increased air density . The Army also had to think about tracer rounds with their different weight. Now mind you, the original designed bullet was practically frangible and was spun so fast to create immense upset upon impact, increasing it's terminal effectiveness.......making it a Wvunder-round until the powder fiasco that ensued.

    Fast forward to the penetrator bullets..........So darned effecient in penetrating hard media that they lost effectivness on soft flesh and bored right through........hence Somalia and current engagements that say the 5.56 sucks for putting a man down with a single shot. So why is a SAW so effective? Cause you're putting 5-15 rounds into a person into a person in the matter of a second or two.
    God show's mercy on drunks and dumb animals.........two outa three ain't a bad score!
  • 5280 shooter II5280 shooter II Posts: 3,923 Senior Member
    Zee wrote: »
    I just figured such an epic high dive into the ego pool as Pegasus made required a deep thought for safety.

    :-)

    "Oh Deep Thought.........have you the answer to the ultimate question?"

    "Yes, I've thought about this quite a bit, and the answer is 42"
    God show's mercy on drunks and dumb animals.........two outa three ain't a bad score!
  • PegasusPegasus Posts: 2,874 Senior Member
    Zee wrote: »
    I just figured such an epic high dive into the ego pool as Pegasus made required a deep thought for safety.

    :-)


    I have been a contributing member of the board for over 5 years now (I think it's even over 6, but who's counting.)

    During that time, I have shared with all of you my journey in F-class competitions. I remember talking here about using my enhanced AR-15 F-TR match rifle and how I was getting to the 1000 yard target with my 80 grain bullets and how difficult it was. I then shared with you the publication of my first article in a gun magazine and how excited I was about it. I shared with you my excitement at being gifted by Mr. Pegasus with an RCBS Chargemaster for Christmas and that even caused some of you to go out and get one of your own. Later on I shared with you the steps I took in transiting to .308 for F-TR and I showed you my first .308 bolt F-TR rifle based on a Ruger M-77 and a superb Broughton barrel. We talked at length about the ammo and the load development and the results. Then the forum melted and all that was lost.

    When the forum was reborn I shared with you my first trip to the Nationals and how I had fared. After that trip I resolved to do better and the first thing I did was build a true F-TR rifle designed from the ground up for that sole purpose; long range F-TR competition. I still remember posting a picture of the rifle that took 8 months to build; the picture of the rifle on a table top over a semi-complete puzzle. We talked about it quite a bit and I shared the intricate details of the load development and my hasty preparations for the 2012 Nationals. Then when I came back from the 2012 Nationals I shared with you the gory details of my crash and burn during the competition. You might remember that I promised to do better the following year.

    During the run-up to this year's competition, I shared with another member here and you my preparations and my resolve to do well. These matches are extremely competitive and there was a huge world contingent present. Lots of sponsored shooters and national teams with coaches and armorers and tons of resources. All I had was my rifle that I had speced out myself, the ammo that I had tuned and assembled myself and the stuff that I had learned and shared with you over the years. As it turns out I did extremely well, exceeding even my wildest expectations and I had a great time. which I shared with you.

    I find it a little more than amusing to read some of the comments that reveal an deep animus toward me coming back from an extremely successful trip to the Nationals and the Worlds. Here we have a 14 year old girl who continually changes her story and admits to not knowing the reasons why things are as they are, tells me I have no reason for saying my ammo is "world-class". I explain why I CAN do that and this is what I get? Really?

    Well, excuse me for not being impressed by these self-styled prima-donnas. I will also add that I have learned my lesson and will refrain from sharing my shooting and competing experiences here as it seems to offend some people. Instead, I may do like them and just contribute snide remarks from now on.
  • bisleybisley Posts: 10,815 Senior Member
    Both sides of this pissing contest are claiming the right to be right, based on their first-hand knowledge and/or experience. I don't know how something like that can be resolved, but it has nothing to do with either's personal accomplishments in life. I enjoy a good argument as much as the next guy, but there's no reason I see for anybody to take their ball and go home.
  • Big ChiefBig Chief Posts: 32,995 Senior Member
    Thanks E-Bob

    So he very well may have had that stash of 75 grainers for his AR (made by ???), but I don't know fer certain, but think I read where the 75 grain ones or at least the V-MAx ones won't fit into a AR magazine. So it would have been single-shot-feed?

    The ones I have are 75 grain Hornady BTHP Match product #2279, not V-maxes.

    Thanks all fer your contributions/opinions/facts/comments/stories. :group::group::group::group::group::group:



    englishbob wrote: »
    My Savage 12 BVSS has a 1 in 9" twist and will give stellar performance with 55 to 69 grainers, but for whatever reason, won't shoot any thing a grain under 55 and most certainly won't entertain anything over 69gns.....

    023df.jpg


    That said, my newest .223 acquisition, a Browning A Bolt TCT Varmint, which has a 1 in 8" twist prefers 52gn bullets over anything else!!!

    Nothing is certain!

    xrts.jpg
    [/QUOTE]
    It's only true if it's on this forum where opinions are facts and facts are opinions
    Words of wisdom from Big Chief: Flush twice, it's a long way to the Mess Hall
    I'd rather have my sister work in a whorehouse than own another Taurus!
  • centermass556centermass556 Posts: 3,618 Senior Member
    I didn't take my ball and go home, I was just at the range all day in an arctic environment shooting M855A1 in M16A2s designed with a 1/7 twist to handle the steel core, Copper jacketed, belgique designed SS109/M855....The rounds and Soldiers performed superbly.
    "To have really lived, you must have almost died. To those who have fought for it, freedom has a flavor the protected will never know."
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