Best twist rate in a 223?


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andym79
April 5, 2012, 05:03 PM
I guys, I am looking to buy a 223, I had assumed a 1:9 twist was preferable to a 1:12.

But then I read that to faster a barrel can lead to poor accuracy with a light barrel!

I would be shooting primarily 55gn SP and 59gn cast bullets (using a RCBS .22-55-SP mould), would a 1:12 be fast enough to get good stabilization of a bullet that size/weight?

A 1:12 twist, would open up a few more rifles to me!

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rcmodel
April 5, 2012, 05:13 PM
A 1:12" will handle most bullets up to 60 grains, and the 63 grain Sierra semi-pointed.

However, a faster twist barrel may shoot light bullets just as well or better then heavier bullets.
I see it all the time in gun test reviews in various firearms publications.

It is far easier to under-stabilize a heavy bullet then to over-stabilize a light bullet.

If you want to shoot 35 grain bullets at 3,700 FPS, you want a slow twist barrel.
For 50, 55, 60, etc, a 1:9 is as likely to shoot them as well or better then a 1:12".

rc

Rapidrob
April 5, 2012, 05:15 PM
1:12 with the 55 grain bullet is ideal out to 500 meters with jacketed bullets. With cast and gas check you will have very good accuracy and pretty good velocity.

BigN
April 5, 2012, 08:22 PM
I have a Savage with a 1-9 twist that shows extreme accuracy with 69 gr hps, 55's are ok but anything lighter starts to fly everywhere.

Got_Lead?
April 5, 2012, 08:42 PM
I'm shooting an AR with a 1:8 twist stainless 16" HB. So far the only load I have worked with is the 60 gn Hornady SP ahead of 3031, and it shoots 3/4" at 100 yds. From my readings, 1:8's and 1:9's are good for stabilizing boolits up to 75 or 80 grains, yet they're not so fast that they will over spin lighter boolits (where they fragment upon leaving the muzzle).

1:12 twists are better for lighter boolits, and may not stabilize over 60 grains, while 1:7's are definately designed for the heavies.

There are probably some match shooters here who can give you the full range of bullet performance vs. twist.

The next question to ask is which barrel finish, stainless, chrome, or moly?

Best of luck with your future .223, they're good fun.

KansasPaul
April 5, 2012, 09:15 PM
I've spent a lot of time playing around with .223 - its been my primary rifle round for the past 5 years and I have hand-loaded rounds from 40 grn to 69 grn. Also played with 1/12, 1/9 and 1/7 twist. Most rifles will shoot well once you dial in the bullet/powder combo that fits the rifle. That said, in my experience, the 1/9 twist offers the most flexibility. 1/9 will still stabilize a heavy bullet provided the length of the bullet itself is not too long - that's where the faster 1/7 twist plays in. For me, my 1/12 rifle didn't really like anything heavier than 50 grains - surplus ammo shot terrible - win. white box 50 grn HP were the bomb. My 1/9 Savage bolt will shoot anything between 50-69 grns accurately, my 1/9 AR likes 55-62 grn. While my 1/7 Colt will shoot just about anything and hold 2MOA. It really comes down to what you want, how important accuracy is, and what your intended purpose is. If I'm going to plink prairie dogs I take the bolt gun (1/9 sub MOA). If I'm out cruising to take a coyote I might just take the Colt because most shots are within 200 yards and that rifle is accurate enough to hit a yote sized target at that range (plus it's about 3 pounds lighter than the bolt gun and I can shoot heavy bullets).

RC spelled it out about right - you just need to figure out the problem you are trying to solve for. Happy searching!

Paul

NCsmitty
April 5, 2012, 09:31 PM
rcmodel It is far easier to under-stabilize a heavy bullet then to over-stabilize a light bullet.

That's likely the only thing that you need to remember, and if you choose a 1in9" twist, you should be fine, and if the selection is a 1in12" twist rifle, you should be equally happy using the bullets that you listed. It's an easy caliber to shoot accurately, and a lot of fun to work up loads for, to your specs.


NCsmitty

Txhillbilly
April 5, 2012, 09:38 PM
I prefer a 1-8,but the 1-9 will shoot just about anything up to 75gr bullets accurately.

joeg26er
April 5, 2012, 09:46 PM
In a 16" barrel AR platform, I have used 1/9 and 1/7

The 1/9 group with anything heavier than 62gr would open up to 3" or more.

With the 1/7 I got tighter groups with a wider range of ammunition. One upper had a definite preference for 68gr with .3" groups at 50 yards with 2moa red dot and a sand bag + two stage RRA trigger.

Caliper_RWVA
April 6, 2012, 12:22 PM
http://ammo.ar15.com/ammo/project/perf_whattwist.html

JPG19
April 6, 2012, 01:01 PM
I prefer the flexibility of a 1:7 and have had no issues running 55gr ammo through mine. I like having the option of running heavier bullets should I choose to take the rifle hunting.

TwoEyedJack
April 6, 2012, 03:58 PM
My PSA AR15 upper has a 1:7 twist. I have found three loads it really likes. 75 gr. Tula and two handloads, one using a 55 gr. Win SP and another using a 52 gr. Sierra BTHP match. I think the faster twists are more versatile.

mshootnit
April 6, 2012, 11:58 PM
I really still like 1/12. Shoots 60 gr. Partitions very nicely.

lmccrock
April 7, 2012, 08:26 AM
How fast are you going to shoot the lead bullets? A 1:12 might not stabilize if the velocity is reduced. Velocity+twist=RPM and RPM+bullet length stabilize.

I had a 12 twist AR and it shot Black Hills 52gr MHP like a laser beam. I let it go because I needed to shoot heavy heavy bullets and Black Hills 69 gr hit the target sideways. :(

Some years back I watched a guy shoot 55gr bullets through a 20" 1:7" barrel. I do not recall the bullet design, or what velocity he had, but the bullets came apart. Today's 55gr bullets might be different, but it was a sight.

jehu
April 7, 2012, 08:54 AM
1:12 for 55gr and under 1:9,7 for 55gr and over.

gotigers
April 7, 2012, 10:51 AM
I prefer 1:8 for 55gr to 77gr. All good ammo i've shot out of my 2 1:8s has been 1/2 to 1-1/2 MOA with low magnified optic. I might get more consistant MOA if i had a high power optic. I prefer the Hornady steel match 55gr for 3 gun and SRS matches. Other ammo out of my 1/8's with good results are Black Hills 68gr BTHP and Fed TRU soft points 55gr.

My 1:9 S&W has been 1 to 2 MOA with decent 55gr ammo. PMC, AE223, XM193, etc.

Wolf ammo is 2-4MOA no matter what gun i shoot it out of.

joed
April 7, 2012, 08:23 PM
The biggest reason for my hatred of the .223 is there are to many twist rates available. The fast twists are trying to make the cartridge do something it wasn't intended to do, but they are successful. To get the best accuracy you don't want to over spin the bullet you're using, to slow and the bullet will keyhole.

The fast twist allows the use of a heavier bullet. If I want to shoot a heavier bullet I'd pick another cartridge and gun for the job. That's why I own a few guns.

So I would determine what you want to shoot and get the appropriate twist. For weights up to 60 gr the 1-12 is fine and that's what I'd want.

I owned a Savage 10fp in .223 for awhile. That gun had a 1-9 twist and I wasn't sure how I'd like it. When I purchased the gun I bought a few boxes of 50 gr Federal ammo. It shot them semi mediocre to maybe groups of 1.5". I tried 45 gr and 40 with equal bad luck. The one amazing bullet was the 69 gr match, which grouped under 1/2" easily on my worst day. I couldn't get anything else to shoot well though.

I bought this gun for varmint hunting and it needed to shoot light bullets. I sold it and moved on to a .22-250.

BUCKrub91
April 7, 2012, 08:54 PM
1:7... mine shoots 55gr loads just fine and 75gr loads amazingly

35 Whelen
April 8, 2012, 02:13 AM
My old bolt .223 (Rem. 788) has a 1-14" twist and and the old worn, pitted barrel shoots 60 gr. Hornady's @ 3123 fps into a smidge over 1" for 5 shot groups @ 100 yds., this without any meaningful load development. 65 gr. Sierra SBT's, no bueno. I'd bet the farm that a 1-12" twist will shoot up to 65 gr. lead core bullets just fine and will handle your 59 gr. cast bullets easily.

Just a note about rifling twist and bullet stabilization:
Bullet stabilization as it relates to rifling twist is dependant on the LENGTH of the bullet, NOT the weight. That's why it makes no sense for someone to believe a 55 gr. Barnes TSX will stabilize in a certain rifle then state that a 60 gr. lead core bullet will not. The TSX, being constructed of solid copper, will always be longer than a lead core bullet of similar weight and in fact it will be longer than many heavier lead core bullets of greater weight. I have a box of 53 gr. TSX's and at .790" in length, they're actually longer (and thus require a faster twist rate to stabilize) than a Hornady 60 gr. SP (.750"), and a Sierra 60 gr. HP (.780") and are almost as long as a Winchester 64 gr. PP (.805").

The biggest reason for my hatred of the .223 is there are to many twist rates available. The fast twists are trying to make the cartridge do something it wasn't intended to do, but they are successful. To get the best accuracy you don't want to over spin the bullet you're using, to slow and the bullet will keyhole.

The fast twist allows the use of a heavier bullet. If I want to shoot a heavier bullet I'd pick another cartridge and gun for the job. That's why I own a few guns.

So I would determine what you want to shoot and get the appropriate twist. For weights up to 60 gr the 1-12 is fine and that's what I'd want.

So, so true.

35W

andym79
April 8, 2012, 03:30 AM
Planning on 59gn cast at 1800 fps, so I am thinking the 1:9 would be the best bet!

tundraotto
April 8, 2012, 08:15 AM
1:8 is great!

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