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-   -   1 in 9 twist in .223 (http://www.firearmstalk.com/forums/f18/1-9-twist-223-a-11586/)

Iowa Plinker 03-06-2009 02:38 AM

1 in 9 twist in .223
 
Recently got me a rifle with a 1 in 9 twist barrel.Since the weather and time hasn't been on my side lately all I got done is got my break in rounds done.Just would like to know if anybody gotten some groups out of 40 grain V maxes out of this faster twist.I knew when I got rifle that light bullets would most likely be out and planned on shooting 52's or 55 grain bullets but you never know?This is a bolt not a AR or ranch style rifle.Thanks Blummer

BILLYBOB44 03-06-2009 03:01 AM

Fast twist bolt gun?
 
:eek:Iowa, what kind of bolt rifle? Most bolts in .22 centerfire have a slower twist (1-12 to1-14) My Rem.Vmt.Spl. 22-250 is a 1-12 and shoots light bullets-40-52gr. well. Most 1-8+1-9 will need at least 55-62gr. bullets to stabilize. You may try the 40gr, but I got a feeling that they won't shoot well in your fast twist barrel.:eek:

Iowa Plinker 03-06-2009 03:13 AM

I just got a 700 VTR.my other .223's have had 1 in 12's so this is a new critter of sorts.Just haven't gotten a chance to try'em for myself yet as it been alittle busy or windy for shooting.Have 50 rounds of FMJ's threw it for break in and then got two 5 shot groups of 52 grain BTHP which showed alot of promise outside of my flyer.Just wonder if them 40's might work since they are long skinny side of the light bullet choices.

Gene L 03-06-2009 03:25 AM

There is a good on-line article by John Barsness, a gunwriter who is knowledgable and tests his premises, on the 9-twist .223s. A lot of rifles are going that way with the heavier bullets. It's on the 24-hour campfire website. Good reading.

He says there is no problem with the faster twist. I guess that's true as I've shot some pretty good groups with a AR with fast twists. It certainly adds versitility to a .223 with heavier bullets.

Folks like to use the term "over-stabalize" but that's not a term that has meaning, as a bullet (or anything) is stable or not-stable, but not over stabale. I'm doubtful you can spin a bullet too fast in .223 Rem so the stability is affected adversely. Maybe with a 22-250 or a .220 Swift, maybe not even then. Bullets can come apart if there is a problem with the jacket on very frangible bullets; never seen it on a .224 bullet, but have on a .17 Remington.

I've got a CZ that I think has a 12-twist in addition to the M 4 9 twist, and every thing I've done informally bear out Barsness's tests. All shoot 55 gr. bullets well enough. The most accurate AR I've owned had 1:7, IIRC, and shot 69 gr. bullets into bugholes. I doubt the CZ would stabalize the heavy bullets as well.

I think it's better to err on the side of faster twist, and it does open up the possibility of heavy, longer-range bullets for longer range shots with high BC possibilities.

A 12 twist rotates a bullet once every 12", or 300 times in 100 yards. A 9 twist turns it faster, do the math, 400 times and a considerable jump in percentages. I don't know if this matters, but it matters the other way, as you need faster twists to turn longer and thus generally higher BC bullets to make them stable. At longer ranges this is especially true.

robocop10mm 03-06-2009 05:54 AM

One of the biggest problems with light bullet/fast twist is the light bullets tend to have thinner jackets. They do not hold up well to the rotational forces of faster twist barrels. You CAN get away with it if you back off a bit on the load. Keep em under 3200 and they will fare better.

The term "over stabilize" refers to the terminal effectiveness of FMJ's. The 55gr M-193 bullet is "just stable enough" to accurately reach the target out of a 1/12 bbl. It will yaw upon entering the target and cause a large wound cavity. If the 55gr FMJ is fired through a 1/7 or 1/9 barrel it will tend to stay stable even after striking the target and pass through w/o causing much damage.

cpttango30 03-06-2009 12:12 PM

if you load a 40gr v-max in that sucker you will never hit anything. Why your going to be blowing up bullets about 5 ' from the barrel.

BILLYBOB44 03-06-2009 12:21 PM

Good Stuff Robo
 
I know on my 22-250, I get better groups at the mid range speed-34-3500 fps. with my favorite bullets 50-55gr Hornady V-Max. They also do a # on groundhogs+yotes at that speed.;)

Gene L 03-06-2009 02:49 PM

Quote:

Originally Posted by cpttango30 (Post 78849)
if you load a 40gr v-max in that sucker you will never hit anything. Why your going to be blowing up bullets about 5 ' from the barrel.

I've shot lots of 40 gr. bullets out of a .223, never blue streaked one yet. I think the Ballistic Tip bullets are designed to blow up around the hollow point (which is filled with a plastic tip.) Jump it up in one of the hotter .22 calibers it might blue streak, but not in my experience, with the .223.


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