1x7 twist rate

Discussion in 'AR-15 Discussion' started by Crazycastor, Aug 30, 2013.

  1. Crazycastor

    Crazycastor New Member

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    I have a 1 in7 twist rate on my 14 1/2 inch barrel. What weight bullets shoot best with this twist. Just started reloading for .223 and and recently got an ar15
     
  2. SSGSF

    SSGSF New Member

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    The .223 Rem shoots a wide range of bullets very effectively, from 35gr flat-based varmint bullets, to ultra-long 90gr VLDs. However, you'll need the right twist rate for your choice of bullet. For max velocity and accuracy with the lightest bullets, a 1:14" twist may be ideal. More versatile is a 1:12" twist that will allow you to shoot the popular 60-64 grain match bullets. (However, a 1:9" twist is needed for the steel-core 62gr bullet used in the M855 military loads, because that bullet is as long as most 70-grainers.) For normal lead-core jacketed bullets, a 1:9" twist will let you shoot up to 73gr bullets. Since most .223 Rem shooters prefer bullets in the 50-73gr range, a good "do-it-all" solution is a 9-twist, unless you're a Highpower competitor.

    For long-range match purposes, long, high-BC bullets are favored for their ability to buck the wind. You'll want at least a 1:8" twist to shoot the 77gr and 80gr MatchKings and 80gr Bergers. To shoot the new 90gr pills, a 1:6.5" is recommended, though a true 1:7" will work in most conditions.

    Overall, what twist rate is best? For varminting we like a 12-twist. The slower twist will give you a bit more velocity, and minimize the risk of jacket failure at high rpms. For general use, an 8-twist barrel will let you shoot the excellent 77gr and 80gr Sierra MatchKings and nearly all varieties of non-tracer milsurp ammo. We'd only select a 1:7" or faster twist barrel if we had a need to shoot the 90gr VLDs.
     

  3. Triumphman

    Triumphman Active Member

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    They say from 55gr to the heavier 77gr works better in this twist, but each Rifle, even with the same Twist, will shoot differently. The biggest result for accuracy, will come from the Powder used, and it's measurement, for your reloads. Primers also play a small part, as to how well they strike. It is/can be a slow procedure with trial shots to determine the best loads for which grain of Bullet that you like. Get yourself a Notebook and be prepared to do a lot of jotting down of test procedures of how you load and how they shoot.
    There's lots of Loads on the Net, to help you, and they will get you very close, but you still need to do your own testing procedures as to how your Rifle shoots with that Load.

    Do you have a Lead Sled to help with accuracy and Rifle steadiness? If not, you really need something to lock down the Rifle. Optics are a plus, and can help, but not necessary. Shoot different Factory Ammos for initial trials(after Zeroing in), to see how well it groups, then pick that, which groups the best, and enhance your reloads from there. This is the way my Dad did it for years as a Gun Smith back in 60/70's.
    Del
     
  4. Triumphman

    Triumphman Active Member

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    Hey SSGSF, I have been hearing(no proof myself) as I don't have any, but some Folks have been having problems on the longer Nosed Bullets in the AR's. They're hanging up on/under the Feed Ramps and causing many Jams.
    Seeing as our new Friend, is wanting to reload for an AR, there might be lots of problems if not Seating correctly, Magazines not feeding right, and BCG, Buffer issues on top of this, if He doesn't know what could be causing the issurs.
    Del
     
  5. Argyle_Armoring

    Argyle_Armoring New Member

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    I prefer 1:7 twist for the AR's I build for customers. You can shoot 55gr and larger/heavier through that barrel.
     
  6. SSGSF

    SSGSF New Member

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    The only time I had this happen to he is , when I did not seat the bullet properly.
     
  7. Crazycastor

    Crazycastor New Member

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    I havent fired a factory round yet in my ar, everything I've shot in it since was new has been reloads that I made. So far I have reloaded about 300 soft point 62 grain bullets and 100 62 grain hollow points and they shot great. My problem is Finding these bulleta are hard. My local LGS has 1000 52 grain hollow points and I don't know how they will shoot in a 1/7 twist. I guess what I'm asking is what weights are the 1/7 twist designed for?
     
  8. DeltaF

    DeltaF New Member

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    The 1 in 7 twist barrel is primarily used in military rifles to stabilize the M856 tracer cartridge, a 63.7 grain bullet, out to 800meters as well as the M855, a 62 grain bullet. It is used in match rifles to stabilize heavy 75-90 grain bullets.

    Source: www.ar15.com/ammo

    Source: www.armystudyguide.com
     
    Last edited: Aug 30, 2013
  9. Quentin

    Quentin New Member

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    Triumphman answered your question above, generally 55 gr and up. You might get away with 52gr but I wouldn't buy a thousand until you know how your particular rifle handles them.
     
  10. SSGSF

    SSGSF New Member

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  11. therewolf

    therewolf New Member

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    I like the match barrel, because I primarily shoot at the range.

    Seems as though the 55grain FMJs, that are so popular

    everywhere now,are a little squirrelly coming out of the

    longer 1/7 HBAR.

    Maybe the 55s won't be too bad through the shorter barrel.
     
  12. Jagermeister

    Jagermeister New Member

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    I have a 1/7 on my Hera Arms. It is a match rifle, but I also hunt with it. I have shot 55 and 62 grain through it with extreme accuracy. I have shot about 700 rounds with no problems. I am quite sure you should not to go under 55 grains. At least fellow competitors tell me this. I have my best results with the 62 grain. Is it ideal? Well try 55 , 62 and 70s range yourself to find out. Your 1/7 twist barrel will have no problem handling the cartridges. Oh, barrel quality/material and uniqueness of each barrel should be taken into consideration. What is ideal for my 15th dynamic rifle may not be ideal for your stick.
     
  13. Rick1967

    Rick1967 Well-Known Member

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    I have a 1/7 twist on my carbine. I have a mid length gas system...in case you care. I shoot 55 grain bullets all the time. They run great. No problem with spinning to fast. However when I run a 77 grain bullet through that gun I can shoot a three shot group at 100 yards with all the holes touching each other. That is less than 1/2 MOA. If you want to shoot heavy bullets for accuracy...you have the right barrel.

    Some people even load heavier bullets than that. They load them so long that they must be fed one at a time because they wont fit in the mag. I haven't taken it to that extreme...yet.
     
  14. DeltaF

    DeltaF New Member

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    The history of the round and reason for different military barrel twists is listed in great, painstaking detail at the websites I referenced in my post. The 856 is longer and heavier than the 855 and can only be used in a 1 in 8 or faster twist barrel. 855 can be used in a 1 in 10 or faster twist barrel.
     
  15. SSGSF

    SSGSF New Member

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    How many times have you shot tracers when you go to the range to zero your weapon.
     
  16. purehavoc

    purehavoc New Member

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    My personal favorite twist in .223 would be the the 1:8 but there are only a few companies out there that do the 1:8 .
    Saying that all but my bolt guns are 1:7
     
  17. DeltaF

    DeltaF New Member

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    Actually when we shoot our M4s we play around with tracers a lot in the evening just for fun. If we're shooting m194 tracers we're typically zeroed for m193. The one time we tried m856 tracers we zeroed for m855. The M855 was about 3 MOA at just outside of 100 yards and we were shooting with it all day with no problems. Then evening came and we started with the M856s. They were all over the place. We were literally watching them curve away from the targets at the last second. The following M855s would then be dead on with no problems. We wondered why M855 shot fine but M856 was horrible. The answer was found later. M855 is fine for 1 in 10 and faster. M856 needs 1 in 8 or faster. All our barrels were 1 in 9 twist barrels. I already cited good sources on this earlier.
     
    Last edited: Aug 30, 2013
  18. Crazycastor

    Crazycastor New Member

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    Thanks guys for the help. Guess I'm not going to buy that 1000 rounds of 52 grain bullets. Will continue looking for the 62 grains that I know the gun likes. You guys gave me some good information. I appreciate it.
     
  19. ZeusEcho

    ZeusEcho Member Lifetime Supporter

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    What kind of barrel and glass?
     
  20. SSGSF

    SSGSF New Member

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    Ok it looks like you have had more training then me.