1:8 or 1:9


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bigred94
December 13, 2009, 10:14 AM
hi there i need some help. i am building a ar15 varmint,table gun. i am now ready to order my barrel, when ordering one must choose a 1:8 twist or 1:9 twist, whats the difference? seems to me that little of a difference will not make much difference on paper. gun will be a 600-1000 yard gun. what should i choose?

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haldir
December 13, 2009, 10:18 AM
1:8, is more versatile.

SomeKid
December 13, 2009, 10:21 AM
IIRC, long range shooting in .223 tend to go for heavier bullet weights, as such, you would probably be better served with a 1:8.

HOLY DIVER
December 13, 2009, 10:38 AM
if i was shooting 600-1000yards i would look at a 1:7 twist......in fact i think i would look into a dpms 308 ar style rifle for that kinda range

Taurus 617 CCW
December 13, 2009, 11:54 AM
I put a Noveske 1:7 14.5" barrel on my AR and never looked back. It has been the best purchase I have ever made for an AR.

Fatelvis
December 13, 2009, 12:01 PM
I prefer minimum 1:8 twist.

Uncle Mike
December 13, 2009, 12:01 PM
1:8" if you must but a 1:7" would be better if your going to shoot the long, heavy bullets out there at 1K.

wishin
December 13, 2009, 12:21 PM
All other things being equal, while a 1:7 handles (stabilizes?) a heavier bullet more effectively, how does it punch at 1000 yds compared to the 1:8?

W.E.G.
December 13, 2009, 12:38 PM
What the heck does "punch" mean?

Are you talking about kinetic energy?
Rest assured, no matter what bullet you shoot out of a .223 at 1000 yards, the only "punch" it has at 1000 yards is enough energy to make it through the target-backer.

Jim Watson
December 13, 2009, 01:00 PM
80 gr SMK is going to arrive at 1000 yds with 225 ft lbs.
About like a light bullet .38 Special.

Rifling twist has no effect on "punch" just stability.

mljdeckard
December 13, 2009, 01:41 PM
And remember, the original rifling was 1/12. The army was using 55 gr bullets that were much more rounded, more like a football. They were intentionally making them yaw, it was very common to get sideways imprints of the bullets going through the paper at longer ranges. When they switched to the A2, they also switched to a 62 gr bullet, which is longer and the edge that touches the rifling (the ogive) is flat. The reason for 1/7 rifling is that tracers need a bit more stabilization than regular rounds. (I have fired tracers in machine guns, but never in an M-16.)

In my experience, 1/9 handles everything very well, including 55 gr bullets. Particularly Barnes all-copper bullets, because they are a bit longer and flatter than lead bullets. The twist rate has just as much to do with the SHAPE of the bullet as it does the WEIGHT.

Maverick223
December 13, 2009, 01:51 PM
All other things being equal, while a 1:7 handles (stabilizes?) a heavier bullet more effectively, how does it punch at 1000 yds compared to the 1:8?It will generally make a smaller hole in the paper, because it didn't keyhole the heavy bullet that you tried to use in the 1:8" twist. :neener:

To the O.P.: I would suggest going with a different chambering if you really want to reach out to 1k, the 6.5Grendel is probably the best candidate in a AR-15 platform and the .260 is even better in a AR-10 (but will be heavier by a good margin). If you are determined to go with .223, it will get the job done, but I would want a 1:6.5" or at least a 1:7" twist to handle the heavier (read: longer) bullets with a high BC.

:)

sarduy
December 13, 2009, 02:30 PM
1:7 so you can use the 55gr for closer range and the heavier bullets for long range

Shadow Man
December 13, 2009, 02:35 PM
Like Maverick said, for reliable 1K hits, the 6.5 Grendal would be a better performing cartridge, yet, I will answer your question: out of the choices, 1:8 would be better, but may I suggest looking around for a 1:7 twist, or one even lower? Also, be careful of the length of bullets you start loading to get that high BC, eventually the rounds will no longer fit in the magazine. Now, if you had a bolt gun, it would be a totally different story...

hoppes-no9
December 13, 2009, 03:47 PM
And remember, the original rifling was 1/12. The army was using 55 gr bullets that were much more rounded, more like a football. They were intentionally making them yaw, it was very common to get sideways imprints of the bullets going through the paper at longer ranges. When they switched to the A2, they also switched to a 62 gr bullet, which is longer and the edge that touches the rifling (the ogive) is flat. The reason for 1/7 rifling is that tracers need a bit more stabilization than regular rounds. (I have fired tracers in machine guns, but never in an M-16.)

In my experience, 1/9 handles everything very well, including 55 gr bullets. Particularly Barnes all-copper bullets, because they are a bit longer and flatter than lead bullets. The twist rate has just as much to do with the SHAPE of the bullet as it does the WEIGHT.
mljdeckard,

Perhaps I am misreading your post, but it seems you are saying that in a given barrel, longer bullets stabilize better than shorter bullets of equal weight?

If that is indeed what you're saying, that's wrong. Shorter bullets will stabilize better (unless you get into the area of "overstabilization"). Stated another way, longer bullets need faster twist to stabilize.

twist calculator (http://kwk.us/twist.html)

If I misunderstood your post, my apologies.

wishin
December 13, 2009, 06:09 PM
Rest assured, no matter what bullet you shoot out of a .223 at 1000 yards, the only "punch" it has at 1000 yards is enough energy to make it through the target-backer.

You can't serious? While it may not be in your guns and ammo lexicon, punch must surely imply more to a brilliant man like you than that.

Maverick223
December 13, 2009, 08:55 PM
You can't serious?I calculated it to be 288ft/lb of energy with a 90gr projectile moving at 2500fps (which should be about right for "best case"), whether that is good enough for anything beyond paper is up to you. Personally, it is a little low for my taste.

:)

mljdeckard
December 13, 2009, 09:07 PM
I'm sorry if I was unclear, I was saying that 1/9 is a great compromise that will handle everything from 55 gr to 62 gr. I honestly haven't tried anything heavier than that.

wishin
December 13, 2009, 11:11 PM
It will generally make a smaller hole in the paper, because it didn't keyhole the heavy bullet that you tried to use in the 1:8" twist.


I don't disagree that it's low, but I wouldn't want to get hit by the 225-280 ft.lbs that it would deliver at that range. I also think that a .308 or 6.5 Grendel would be a better choice.

Maverick223
December 13, 2009, 11:19 PM
I don't disagree that it's low, but I wouldn't want to get hit by the 225-280 ft.lbs that it would deliver at that range. I also think that a .308 or 6.5 Grendel would be a better choice.Huh? In the above quote I was referring to the fact that a heavy bullet would keyhole rather than punch a clean hole. FWIW, I'd rather not get shot with anything, including a BB gun, doesn't mean I consider that to have adequate power either, though 288fpe would be fine for most varmints (assuming P-dogs, G-hogs, et cetera).

jbech123
December 14, 2009, 09:49 AM
I was saying that 1/9 is a great compromise that will handle everything from 55 gr to 62 gr.
I shoot 77gr black hills factory loads in my 9 twist all the time, and it doesn't keyhole. In fact it shoots extremely well, and difference in group size between the 77gr, 62 gr, and 69gr is almost certainly inconsistency on my part, not my rifle.

T.A.Sharps
December 14, 2009, 02:43 PM
I was in the same worry as the OP, being more accuracy oriented with my purchase.

Basically the twist rate is directly related to the bullet you want to, or can shoot.

I ended up going with a 1/9" twist barrel for half the reason I wanted a heavier/stiffer barrel for my 16" carbine, and the other half is that 95% of all 223/556 ammo available in my area is 55gr.

I would really prefer to shoot 60-80 grain bullets, but I don't reload yet, and that ammo is more expensive and has less commercial options locally.

I would rather of had a black coated 18" bull barrel with a 1/8 twist, and all the ammo to shoot, but it didn't seem realistic, if I start reloading I can always get a new Krieger barrel and free float tube for it.

bigred94
December 14, 2009, 07:14 PM
thanks for all the help, just one thing what does keyhole mean? also i am looking at the 69, 75 and 77 grain, what i understand the 1:8 will work best right?

jbech123
December 14, 2009, 07:34 PM
keyhole means the bullet hits the target sideways, or really any way besides point first. This can happen if the bullet is not spun fast enough to stabilize it. The longer/heavier bullets need to be spun faster to stabilize. For your needs an 8 twist would work, but if you handload and are thinking you might go to 80 or above, it wouoldn't hurt to get a 7 twist. The only disadvantage is you could have issues if you shoot really light bullets(like 40 gr) with really thin jackets. I've heard you can basically spin the bullet apart, although I've not ever witnessed this happening.

wishin
December 14, 2009, 10:06 PM
T.A.Sharps, I've been using 68 gr. Ultramax ammo in my mini-14 and have been very pleased with it; reasonably priced too.

http://www.ultramaxammunition.com/rifle.php

RockyMtnTactical
December 15, 2009, 05:54 AM
I like the 1/8 the best. I wish this was THE standard.

bigred94
December 15, 2009, 02:51 PM
ok, i think i want to go with the 1:8 so i can shoot the heavy 77 and 79s. i can not find a rifle kit that has a heavy 24" black 1:8 barrel. does anybody know of one?

Maverick223
December 15, 2009, 05:23 PM
Red, be aware that some 77gr bullets will require a 1:7 or better to stabilize properly.

:)

Dr. Tad Hussein Winslow
December 15, 2009, 05:53 PM
gun will be a 600-1000 yard gun

That's an extremely long ways for a "real" rifle caliber, let alone a short/mid range caliber. If you're really and truly trying to stretch the .223 rem into that long / very long range role (for some odd reason), the answer is clearly "none of the above" - 1 in 7" twist for crazy long bullets in the 80-100 gr range.

Or, you could make your life simpler, your face smilier, and your targets better by just getting the caliber to handle the job (.243 Win or larger).

Grassman
December 15, 2009, 06:01 PM
My new Bushmaster predator comes with a 20" 1:8 twist. I'm looking forward to finding out for myself.

bigred94
December 15, 2009, 06:30 PM
i know the 223 may not be the easist thing for 1000 yards, but i shoot a bolt 308 at 1000 now and i want to shoot the 223. where can i find a kit with the barrel i need?

Maverick223
December 15, 2009, 10:42 PM
Or, you could make your life simpler, your face smilier, and your targets better by just getting the caliber to handle the job (.243 Win or larger).Eh, the 6.5Grendel will get the job done, and still fit in the AR-15 upper.
where can i find a kit with the barrel i need?kriegerbarrels.com, but you'll need to plop it in an upper (or have a gunsmith do likewise), I would suggest a really good bbl for that range...or really big targets. :D

bigred94
December 17, 2009, 06:38 PM
ok i know what i want i think, just one question left, what will a heavy bull barrel have over a standard barrel as far as shooting long ranges?

jbech123
December 18, 2009, 01:55 AM
Quote:
gun will be a 600-1000 yard gun

That's an extremely long ways for a "real" rifle caliber, let alone a short/mid range caliber. If you're really and truly trying to stretch the .223 rem into that long / very long range role (for some odd reason), the answer is clearly "none of the above" - 1 in 7" twist for crazy long bullets in the 80-100 gr range.


someone forgot to tell this guy about the limitations

http://www.longrangehunting.com/articles/shooting-223-mile-1.php

Maverick223
December 18, 2009, 02:53 AM
what will a heavy bull barrel have over a standard barrel as far as shooting long ranges?A bull bbl (or other heavy profile) will have a greater stiffness and moment of inertia than a smaller profile, fluting the barrel can also help as it relieves a little weight (which can make it have better resilience to flexure as it heats up, and making it lighter to carry) for a better strength to weight ratio, and has a greater surface area (for faster cooling, but at the expense of less capacitance making it also heat up more rapidly). In an AR-15 you are limited in your barrel profile choices, but for distance varmint/target shooting I would want a Krieger 1:7" (or 1:6.5") heavy fluted barrel in chrome molybdenum (I'm not real big on SS but don't really have a problem with it) with a Wylde chamber (so you can still plink with cheap ammo).

:)

T.A.Sharps
December 18, 2009, 06:00 AM
It should be said that the thinner a barrel, the faster it will heat up.

This is important to consider because if the heats up, it will change how it flexes and vibrates through a shot. And they all do, if you ever youtube some high speed video of guns shooting you will see how they flex and warp.

If you change how the barrel vibrates, you change at what position the bullet leaves the barrel, during the flexing and vibrating, changing your impact point.

If your barrel is short and fat, it will be really stiff, and vibrate very little, and accuracy would be less susceptible to this problem.

Free floating is also related to this, if part of your for-stock warps, like wood in heat and moisture, it will touch the barrel differently, and affect the vibrations. It is also why you never rest your barrel on something when you shoot.

Also, I would like to add that the benefit on flutes is still in controversy.

Some say it actually doesn't add to stiffness, but takes away from it since you are taking away material.
...as well as the weight factor is not enough to make a difference in how much you feel holding it.

Few other things, but you can look them up.

Personally, I don't know, I have not experienced them enough to say, but they seem like an added variable to your barrel's quality, so I rather stick to the tired and true.

wishin
December 18, 2009, 09:24 AM
gun will be a 600-1000 yard gun

That's an extremely long ways for a "real" rifle caliber, let alone a short/mid range caliber. If you're really and truly trying to stretch the .223 rem into that long / very long range role (for some odd reason), the answer is clearly "none of the above" - 1 in 7" twist for crazy long bullets in the 80-100 gr range.

someone forgot to tell this guy about the limitations

http://www.longrangehunting.com/arti...223-mile-1.php

This is akin to economists today. All these experts with all these differing opinions!:)

Maverick223
December 18, 2009, 12:51 PM
Also, I would like to add that the benefit on flutes is still in controversy. Some say it actually doesn't add to stiffness, but takes away from it since you are taking away material...as well as the weight factor is not enough to make a difference in how much you feel holding it.It is controversial, but there is no question that it can make the barrel stiffer, due to reducing its own weight at the muzzle, if fluted properly (but it can be weaker if fluted incorrectly) as well as make the rifle significantly lighter.

:)

Mr. T
December 18, 2009, 03:19 PM
I have heard that the tighter the twist rate, it is going to start to restrict how low you can step down in bullet weight also; I'm not sure if that's a factor for you. I have a buddy who claims that when he replaced his regular barrel 1:9 to a 1:7 he couldn't shoot his lower weight varmint loads any longer because the twist rate was causing the jackets to spin off the bullet before it got to the target. I don't know if that was an ammo issue or if there was some reality to it. He said he was shooting 50 grain American Eagle BTHP's. I've shot American Eagle and they seem to be high quality ammo to me. I have also been told that tighter twist rates do take "punch" off the bullet. It was explained to me as such: A powder charge in a round only has so much energy it can produce -- firing the same ammo through two different barrels with regard to twist rate will result in different results. Let's for example use 1:7 vs 1:9. Same ammo fired through those barrels at the same let's say 300 yards will result in the 1:9 round being quicker but less accurate; it will also carry slightly more energy down range -- reason for that being less energy is being expended in spinning that round in order to stabilize it. The faster the round spins, typically the greater the accuracy, however you do sacrifice a little speed and "punch".

bigred94
December 18, 2009, 07:09 PM
thanks for all the help once again i know the 223 is not best for a 1k shoot but i want a new task. i shoot a 308 at 1k and its down to a science so i want something new, hints all the guestions on twist rates and barrels. please dont stop with the feedback, its all been alot of help.

Maverick223
December 18, 2009, 08:51 PM
I have a buddy who claims that when he replaced his regular barrel 1:9 to a 1:7 he couldn't shoot his lower weight varmint loads any longer because the twist rate was causing the jackets to spin off the bullet before it got to the target.True, spin it too fast and it will actually spin apart in flight. I wouldn't try anything sub-55gr. in a 1:7" or 1:6.5" twist (and you may have to use 62gr.+ for the 6.5" twist), but for reaching out that far you really need all the advantage you can get from those wee-bore poodle poppers. My thoughts are go with a 1:7" if you want to "try out" 1000yds and 1:6.5" if you are serious about reaching out that far (and intent on using the .22cal to do it). For typical "informal shooting", plinking, light varmint hunting and the like (which is all I use my .223 for) a 1:9" is my personal choice. It sounds like your buddy uses his likewise and would have probably been better served by the 1:9" (or 1:8") as well.

Mista Tee; by any chance do you load up on gold chains and have a peculiar fondness for Mini-14s? :D

:)

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