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1:7 or 1:9?

Discussion in 'Rifle Country' started by blackops, Jan 6, 2011.

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  1. blackops

    blackops Member

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    Fixing to get a Spikes LE, not sure though. Wondering (from the guys with experience) how do you like the 1:7 twist? I'm not sure what kind of diet I'm going to run this thing on, but I'll keep it inside 400yds for sure. Anyways, just looking for some opinions. Thanks guys.
     
  2. HKGuns

    HKGuns Member

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    Really depends on what weight bullets you are going to shoot. Betting you'll be on a common diet of the very common and very cheap 55gr the 1/9 is ideal.
     
  3. MMcfpd

    MMcfpd Member

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    Unless you think you'll be shooting the really light loads, as in 45 gr. or less, get a 1:7; it'll do fine with everything from 55 gr. and heavier.
     
  4. migkillertwo

    migkillertwo Member

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    better for heavier loads (75gr.). 1/7 stabilizes 55gr and 62gr bullets fine.
     
  5. carbine85

    carbine85 Member

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    Best accuracy will be from the 1:9 with the more common lighter bullets. I personnely think 1:8 is the best choice.
     
  6. FredT

    FredT Member

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    1 in 8 gets my vote also.
     
  7. Jim Watson

    Jim Watson Member

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    Yeah, but if Spike doesn't offer 1-8 it isn't much help to the OP.

    1-9 will handle 69 gr match and 62 gr M855/SS109 hardball for sure, maybe 75 gr maybe not. All lighter bullets like 55 gr imitation Viet Nam era M193ish and 45 gr WWB varmint loads will be fine.

    1-7 will handle up through 82 gr match, likely 90 gr (single loaded only), and the M856/SS110 tracer. It will shoot 55 gr GI, might be erratic with light varmint bullets.
     
  8. blackops

    blackops Member

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    As Jim mentioned Spikes doesn't offer a 1:8. I'm hearing mixed opinions here, but I'm taking it that the 1:9 should be fine just maybe a bit more accurate with the heavier bullets.
     
  9. Waywatcher

    Waywatcher Member

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    If you want to reliably shoot 75-77 OTMs, which are the best thing going for terminal effect in .223, you'll need 1:8 or faster. The 1:9 twist may keyhole these.

    If you want to shoot lightweights, like 40-55 at the most, get a 1:12. I don't have a use for 1:9 twist in .223.

    I would definitely get the 1:7.
     
  10. lobo9er

    lobo9er Member

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    my vote is 1-7 more versatile. If anything you may shoot heavier bullets more often than 45 grain stuff. but you also may not notice. if your shooting 100 yards i dont think it matters much. depends on what you want the rifle to do.
     
  11. 1stmarine

    1stmarine Member

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    Stick to the facts of ballistics and not opinions:
    If you use mostly lower grain bullets (most up to 67gr) then 1:9 is perfect.
    If you wan to shoot ocasionally 70gr, 75gr Hornadys or even 77gr 1:8 is perfect and still not too fast for a 50gr bullet.
    If you want to shoot ONLY 70gr, 75gr and even 80gr or 90gr bullets then get the 1:7 or even a 1:6.5 but here you have a problem.
    At 77gr most of the good bullets (slender high bc bullets) you are maxed out in COAL (Cartrige Overall Length) to properly feed in an AR magazine.
    The 77gr SMKs and 77gr VLDs are all great but more typical in target barrels 20" and above. Some 80gr bullets and 90gr bullets need to be single feed and you also need to consider the gap before you hit the landings so only long range target shooters do this.
    A 1:7 twist of rate with low grain bullets is so fast that the jackets might come apart (I have seen this and done that) and also you want the bullet to do something when it gets there so for most it is too fast.

    So the ideal for the average nice upper is 1:8.

    1:7 is not required only if you are always going highest grains(75 and above) and NEVER low grain like 40gr bullet.

    I hope this helps.
    Shoot often. Stay safe and never forget our veterans.
    E.
     
  12. sappyg

    sappyg Member

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    i'm not sure exactly what the OP is asking here. the only things i've ever shot with my AR's was paper and 1/9 twist works fine for that. i've never bothered to load heavier bullets and i no longer get so involved with the bullet of the week. TMK the only reason current M4's have 1/7 twist is to stabilize a tracer round. seems to me the market is just trying to create a need in order to sell specialty bullets. that, at a premium i might add.
    i've never really been so inclined to shoot anything heavier than 62 gr. bullets in an AR but then again i don't really have a specialized need to either. the matter really comes down to the intended use. beyond 300 yards and i would seriously consider a completely different cartrige.
    day in day out i could be happy with 1/9 twist and not give it a second thought.
     
  13. HKGuns

    HKGuns Member

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    Popcorn time!
     
  14. 1stmarine

    1stmarine Member

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    sappyg
    I think you are right. If you never want to try a 70gr bullet 1:9 is better. Because I like to have hornady TAP 75gr for defense ammo I have a 1:8 but it is me. Not better or worse I am saying look at the bullet/s you want to shoot first and then decide on the system, not the other way around.
    I just do not understand the need to vote in something like this. It comes to the intended purpose. I have 1:9 and 1:8 and 1:7 and others so everyone has a meaning and a purpose as I
    explained above.
    By overspining you loose energy as well. 1:7 will take apart some jackets in a low grain bullet specially the cheaper ones not bonded. This is a fact nothing else to discuss here.
    Cheers.
     
    Last edited: Jan 6, 2011
  15. FredT

    FredT Member

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    I got salt and butter.
     
  16. kwelz

    kwelz Member

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    I have seen some 1/9 barrel have problems with bullet weight as low as 62 grains.


    I have heard this said a number of times but never seen any data to back it up.
     
  17. sappyg

    sappyg Member

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    i'm always down for some jiffy pop. ;)
     
  18. HKGuns

    HKGuns Member

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    Pass the butter please!
     
  19. 1stmarine

    1stmarine Member

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    kwelz,
    Please let me better explain. lets review the facts once again.
    A 62 grain is a pretty consistently sized bullet. The reason the military has the colt in the 1:7 is to be used with efficiently with the penetrator SS109/M855 as well as the marksman/sniper Mk262 (that is nothing but a 77gr SMK). A 1:8 will achieve the same. As a retired marksman I used to carry several of the SMK clips with me.

    A 1:9 should stabilize the M855 but might not do harm faster in the newer with the titanium rods (a tad longer) so this is why I suggested the 1:8. I am having a hard time believing that anyone doesn't want to try a TAP round or an SMK so yet another reason for the 1:8 and The tracer will do ok. You will do fine with the 1:9 if all you shoot is the M183 (55gr federals), M855 and lower.

    If you go with the 1:7 IT WILL BE OK, but just be aware of the low grain cheaper bullets SOMETIMES coming apart and the more drag on the bullet and thus lowers velocity.

    Look for other problems, the ammo, the barrel out of spec of something else, not the twist of rate.

    I don't know how much shooting you guys do but even the other day one guy using a low grain bullet a jacket came a part and normally this just shows as bad accuracy but the other day it came apart at the muzzle (something that doesn't happen that often) and because he had a long brake pieces of the jacket came back flying back at us. That's why you need to make sure you always have glasses and good ones. Again a jacket coming partially a part just comes down to: Why my super nice AR cannot group s#%t with 1:7rate. ...well the answer is cheap low grain bullets with jackets that might not fully disintegrate but surely deform the bullets you are shooting.

    I don't know what else I can tell you guys. There are some good books about ballistics, barrels and even the history of the AR is a nice reading and can learn about your systems.
    Shoot often, stay safe and don't ever forget our veterans.

    Cheers,
    E.
     
    Last edited: Jan 6, 2011
  20. FlyinBryan

    FlyinBryan Member

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    can i ask what the popcorn thing means?
     
  21. 1stmarine

    1stmarine Member

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    Kids.
     
  22. sappyg

    sappyg Member

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    forget the pocorn. it's a FOOD FIGHT!
     
  23. Jim Watson

    Jim Watson Member

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    My 6.5 twist AR, optimized for single loaded 90 grain bullets, will definitely spin a thin jacketed bullet apart. It will blow up or bend into funny shapes even the 90 gr Sierra if loaded hot enough to reach 1000 yards supersonic. I had one target scored nothing but Xs, 10s, and misses, the latter from bullets too distorted to reach the target.
    It will blow 75 gr Amax to smithereens, silver streaks in the sunlight 1/3 of the way to the target.
    Nothing I have found but but a JLK or Berger VLD will take the stress of a 1000 yard load.
    The SMK and Amax are fine at 600 if loaded down a bit.

    If the OP wants to shoot 400 yards from the magazine, he might should be looking at the 1-7 for 77 gr length tolerant bullets.
     
  24. 1stmarine

    1stmarine Member

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    Jim Watson,
    Thanks for more supporting facts. The result of the twist of rate is not so aggressive in the carbine barrels but defently in a long match barrel 20 or 24" it will ALWAYS rip the small bullets apart.

    This is what quick load help says about the 1:7 rate....
    1:7 or 6.5 / 90 bt vld (not highly recommended unless you want to shoot the VLDs) Quick Load is a software that senior reloaders and professionals use to find the appropriate load for specific purpose. It comes with an ocean of knowledge so I wanted to post this here too.

    In any case an M4 barrel in 1:7 IT IS NOT WRONG. That's why they are offering them but take into account what we are explaining above, especially if you find a great deal in old surplus 5.56. It will take them apart and your groups will suck.

    There are many great 1:8 barrels out there.

    Cheers,
    E.
     
  25. FlyinBryan

    FlyinBryan Member

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    i am assuming you are talking about 1/7 barrels?

    up until this past christmas day i would have just written this off as another one of those things ive heard, but not seen, (ive actually been quite critical on this claim here in the past) but on christmas, we loaded up some 45g varmint bullets (sierra's varminter bullets). they were not even loaded to max pressure. 27g of varget, chrono'd, at 3300fps. more on that in a minute.

    LOL, they looked like little grenades. anywhere from 10-50ft out they would pop and look like a little firecracker going off in mid-air. you could even hear it.

    back to the chrono. we started checking velocities before we started trying to hit anything with them. (and before the 1st one "poofed")

    1st one chronographed @ 3313, 3323, and the 3rd one "poofed" right over my alpha chrony and busted one of the shades......... at first i thought my brother had shot my chronograph, but as we inspected it, it looked like someone chewed up a lead fishing weight and spat it all over the inside of the chrono, and thats when we realized what happened.

    we started shooting them and watching it closely, and at least every 3rd to 4th one did it. if we shot faster and warmed the barrel it seemed to get worse.

    if i didnt see it i would have never believed it (ive said everything here short of calling ppl liars over the subject before. to whomever i was talkign to, my apoligies, i was wrong)

    out of a 1/7 barrel, they were
     
    Last edited: Jan 7, 2011
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