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A lot of 223 Remington bolt rifles come with a 1:9 twist which provides flexibility for shooting bullet weights up to 70 grains or maybe higher in some cases. If you wanted to dedicate a barrel to shooting only 50-55 grain bullets, would a 1:12 twist be a clearly better choice than the 1:9? Would any differences be noticeable to the average shooter? Could the differences be load specific?
My buddy shoots a 10 twist for the light stuff (22" Bartlien) He will
bughole his groups at 100 with the 50's. Easily shoot's 1/2 MOA with
the Mil 62's. I personally keep with an 8 twist to cover all the bases
up to the Sierra 77's, which I mainly shoot.
I have two .223 rifles with 1:9 twist barrels that shoot 52 grain Sierra SMK #1410 and Berger Flat Base #22408 and 53 grain Sierra SMKs #1400 as good as anything else.
They are not cheap bullets but they don't break the bank either.
Both barrels also shoot 40 and 50 grain bullet almost as well.
Not surprisingly, both rifles also shoot 69 grain bullets about the same, especially the Sierra SMK #1380 and TMKs #7169 and Nosler CCs.
I recently tried both with 77 gr Sierra SMK #9377 and TMKs # 7177 and both rifles both shot them great, even though a 1:9 barrel isn't supposed to stabilize 77 gr bullets. One of the two shoots the 77 grain Sierras better than any other bullets.
I do use a slower burning powder set for bullets heavier than 60 grains.
In my experience and I measure all the groups I shoot and keep copious records, a faster twist doesn't mean a barrel won't shoot lighter bullets better or worse than heavier bullets.
Bullet body length, powder choice, and the bullet quality (amount of QA you pay for during manufacture) seems to make more of a difference.
For example, I have never found a 55 grain bulk bullet that shot anywhere nearly as well as a Berger #22410 55 grain bullet.
The Berger is more expensive, has a higher BC and there is almost no variation in shape or bullet length.
Not so with the bulk 55 grain bullets that are mostly made for low cost plinking.
My data says that you get what you pay for when it comes to bullets if you are really interested in accuracy.
I've had the same experience as CFJunkie.
Here is a lot of info including some on twist rate:
https://www.6mmbr.com/223Rem.html
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Thanks for the info. I have had pretty good performance in my 1:9 barrels with the 52/53 SMK, 53/55 V-Max, 60 V-Max and the 60 Berger FBHP. The lighter Bergers shot good in limited use but I haven't worked with them much. I have yet to find a good load for the Sierra 60 TMK or the 69 SMK.
It sounds like I shouldn't be overly concerned with the twist rate being too fast. I guess if I were to invest in another barrel for my spare action, it would be a 1:8 or 1:7 for heavier bullets.
In a .223 the standard 1-9" twist will shoot most anything out there under 70-75gr. Even a faster shooting 22-250 with a 9-twist will shoot most bullets down to 45gr (never tried 40's). That said, bullet construction, particularly jacket thickness, can and will have an impact. Probably not near as much so with the slower 223 velocities, but I've run into a few 50-55gr bullets over the years that couldn't handle the faster twist due to having a very thin jacket and they would just blow up (grey mist club) somewhere between 25-50yds at the faster 22-250 velocities.
1-12" was the standard for .223 for a few decades and is still the standard for many factory bolt-action rifles today. A 1-10" twist is kind of the happy medium that still allows you additional flexibility in bullet selection.
Like J Baker, I've had the grey mist occur with my .22-250 with 40 grain Nosler BTs at about 4200 fps and it only had a 1:14 twist.
Never had it happen with 50 to 52 grain bullets with my .22-250, although I never even approached that velocity with the bullets above 40 grains.
I've never seen a grey mist cloud with a 1:9 twist .223 even with 35 grain bullets.
For some data on 77 grain bullet performance in a 1:9 twist barrel:
https://www.savageshooters.com/showt...9-twist-barrel
Depending on bullet speed and length of bullet, you can use a
slower twist rate as the speeds get higher. Jump on "JBM" and
use the twist rate calculator, and bookmark it.