Tuesday, May 27, 2014

In Defense of the 12 twist. (or the untwisting of the mind)

Guest Post:  Allabaster

*** Editor's Note:  This is the first of the new guest posts.  Fair warning...  these gun posts are not going to be written for everyone.  This isn't mass market stuff.  This is gun nerd eggheadery.  Big time.  If you want dumbed down mass market crap... there are plenty of places to find it.  Sometimes you'll even find it here.  But this is one of the few places you will find articles like this.  Also... you will find some unique spelling here.  Allabaster is an aussie.  Deal with it.***

Few things can bring about humility and clarity of thought than being forced to recant from an opinion derived from logic and reason when it is contradicted by the empirical results of practiced application of the before mentioned logic and reason. To stubbornly cling to the questionable fruits of your abstract faculties in spite of the witness of your lying eyes is little more than an exercise in self indulgent hubris.

Therefore being a man who has learned, via the unapologetic hammer of reality’s consequences, to be wary of his own sense of creeping hubris from spates of overactive abstract analysis, I have recanted my position of the ideal twist rate for the 223 Remington in a practical game and varmint rifle.

Now the 223 Remington, being an almost interchangeable round with the 5.56x45mm NATO round standardized in the 1950’s, was always going to have far greater focus of attention placed upon it than other cartridge offerings due to the economies of scale and dedicated platforms that flow to the sporting shooter market from widespread military applications. For this reason it is adapted to game, target, varmint and battle rifle applications with a far greater variety of projectile designs and weights than would ever be afforded a cartridge without the benefits of widespread popularity beyond its own inherit virtues.

The former NATO standard, the 308 Winchester (7.62x51mm), has less in the way of variation of ideal projectile weights, and therefore barrel twists, for intended use as the typical 155 to 175 grain weights are as popular for hunting projectiles as they are for the target variety.

Now my own recantation, mentioned many paragraphs passed, involves the belief that every 223 made should be equipped with a 1 in 8 or thereabouts twist rate to take advantage of all projectiles up to around 75 grains with their superior ballistic properties and sectional densities. This was my firm, somewhat informed, opinion until circumstances conspired against me during my reasonable priced bolt-action 223 varmint build of a few years ago.

The rifle in question, which I have written of many times before, is my Howa 1500 varmint. I have been very impressed with this model of rifle for its relatively modest price and high potential for consistent accuracy out of the box. The only non aesthetic downside I could detect at the time of planning my build was the lack of barrel twist options, namely the 1 in 12 for the 223, which would in turn restrict the range of projectiles I could reliably stabilize. Ultimately the monetary handicap known as “being a student” forced me to blunt my high minded and fast twist aspirations and accept the everyman’s lot in both life and rifle barrels.

With the rifle intended to target varmints out to 400m I decided upon the Hornady V-Max line of projectiles and had great results with the 50gr boat tail version in both snap target matches and with predictability of shot placement in the field. However this projectile had its own inherit limitations as it, and most other projectiles of its kind, are intended to be used in everything from a 22-250 to a 222. This meant the projectile’s ogive shape had to accommodate the throat length of many possible cartridges across the board, not just the 223 dimensions for which it was being used in my case. Consequently the ogive shape is quite angled and less aerodynamic that it could potentially be given the projectile weight.

A relatively new 53gr V-Max offering from Hornady however makes the most of the popular 1 in 12 twist 223 combination. By being intended for use only in the 223, the new projectile can replicate the ogive dimensions of the 75 gr A-Max target projectile. This provides a marked ballistic co-efficient (BC) increase of .290 for the 53gr vs .242 of the 50gr for a very modest weight gain. This does not provide the BC of a 68 grain target projectile, whose BC of around .350 requires a 1 in 9 twist rate, but it mitigates the gap in BC which is predominantly caused by the ‘one size fits all’ nature of most 22 cal projectiles.

What this effectively means is that for a 223 rifle is that projectiles with a length and weight beyond what a 1 in 12 twist can stabilise offer only a real benefit for those who intend for their 223 to engage in extended distance target applications where the improved ballistic properties are the major deciding factor. For any rifle that is intended for use on game or varmint the lack of access to the high BC heavy projectile is not a relevant limitation as such projectiles are not intended for use on either, although they may be arguably be used in a reduced capacity.

It is my hope that there will be, one day, a greater variety of popular chambering specific projectiles released to the market which will open new possibilities for the hand loader to make the most of their common rifle configurations.

21 comments:

Athor Pel said...

You say one thing at the beginning and another at the end, to paraphrase, "I wasn't happy with the 1 in 12 twist rate of my new gun but I've since changed my mind and I'm really happy about it."

And the conclusion states, "As long as I only shoot low weight bullets everything is fine and I probably wouldn't need to shoot heavier bullets anyway."

That really doesn't sound all that pleased.

Besides, the way you started this article I was expecting to read about something truly new but all you ended up doing was confirming established knowledge.

Bait and switch, that's what this is, bait and switch.

Nate said...

***squinty eyed dirty look***

Your summation is incorrect. He started out being a fast twist snob... self-assured through reason and logic that 1 in 8 was far superior to 1 in 12... but after he built his varmint rig with a 1 in 12 he was forced to admit that his assumptions about the slower twist rate were incorrect.

It's not something new... its a snobby gun nerd admitting he was wrong and in doing so pointing out some of the limitations of snobby gun nerdery.

Nate said...

As bullet techonology has improved I think you'll see higher twist rates becoming more common. A great example of this is the 22-250. You can get them in 1 in 12 or 1 in 9 from the factory. The 1 in 9 allows for heavier (60gr +) bullets and let the rifle really reach out there.

Res Ipsa said...

I think it's important to remember why the AR and the 223 got such a bum rap on accuracy. The first reason is Col Jeff Cooper. Cooper, for all his other contributions to shooting, had two things he hated and was passionate against, those were, the 223 and long range shooting. The second reason is that the AR platform was built "loose". The reason for that was to ensure the gun went bang every time the trigger was pulled in combat.

Any well built 223 is capable of good accuracy about to about 500 yards, regardless of barrel twist rate. A 1:10 twist should get you to about 600 yards a 1:7 or some 1:8 will get you to 1,000. Beyond 1,100 is beyond the capabilities of the 223, in most configurations.

FWIW the AR is capable of beating Coopers 20/20 challenge. I've seen it done. For those of you who don't know the 20/20 is 20 shots in 20 seconds on a standard man sized silhouette at a distance of 1,000 yards, fired from any standard shooting position.

Nate said...

I know savage has a competition rifle that has a 1:7 twist. That's pretty fast.

But your point is well taken Res... the .223 is almost permanently attached at the hip to the AR platform to the point that when you discuss it folks just assume you're talking about an AR.

patrick kelly said...

Here's a competition .223 with some impressive results at 1000 yds:
1000yd223

31" barrel, 1:7 twist, pushing 90gr vld to 2900fps.

Allabaster said...

That is the funny thing about the 223 here in Australia, AR's have been gone from the shooting scene for nearly 20 years so they are mostly a bolt gun proposition. This means that they are typically known for very good accuracy especially for contract kangaroo shooters who have to take only head shots by law, that means practical MOA from point of aim at 200m with the maximum distance you could be confident of tagging a 2 inch area would be 3-400m.
Also worth noting that most 223's here are coming out of a 22-24 inch barrel so you can crank up the muzzle velocity compared to most AR's that are not dedicated varminters.

Nate said...

I note the competition .223 in Patrick's example has a savage 12 action.

Giraffe said...

I have a 10 or 12 twist on my ar. I'd prefer a 9.

But honestly, if i get far enough out there that a 55 grainer won't cut it I'd be better off with an ar 10. We've used the ar's for coyotes and you can't see the bullet hit when you get one on the run. Half the fun is seeing the dirt fly and the coyote dodging.

Outlaw X said...

The problem with a fast twist and a high velocity is bullet integrity. A 50 grain (copper jacketed lead) bullet with a standard 1:12 twist loaded max out a 22-250 will disintegrate within the first 75 yds. Heavier bullets are needed for any long range shooting. I like the 60 Grain in my 220 swift and the 55 grain in my 22-250. I have smoked 55 grain bullets in dense air scenarios with my 22-250.

I do like the tracer effect smoke trail though before the come apart.

Outlaw X said...

One other thing. 1000 yd shooting is not possible with a .223 below 1000 ft in altitude they will start tumbling well before the 1000 yd mark.

Nate said...

Outlaw,
I think the reason you're seeing these twist rates is the rise in popularity of solid copper bullets. They can handle it.

Res Ipsa said...

I only have one AR. It does great till about 600. Then the lighter bullets lose stability. My main problem is that I have a 1:10 twist. It's too slow to stabilize the heavy match kings or Bergers. I love the varmint grenades. Nothing says good shooting like a fine red mist.

Nate said...

Varmint Grenades!

"daddy what's that red stuff on that rock?"

"That's liquified prairie dog son."

"sweeet."

Nate said...

Is that AR your go-to varmint rig or do you have something else you generally perfer?

Athor Pel said...

To tell the truth, yes, I was surprised when he said he bought a gun with a 1 in 12 twist rate for the .223. I didn't even know such a thing existed. I was only aware of 1 in 9 as being the slowest twist rate for that caliber. Of course that's on an AR platform with likely a less than 20 inch long barrel.


Nate,
I got idea for a blog post about guns. It's about the surprises I had when I started buying and shooting pistols. After I write it up I'll mail it to you.

Nate said...

Thanks AP

Res Ipsa said...

Is that AR your go-to varmint rig or do you have something else you generally perfer?

I use the AR fairly often. I like using a 7-08 and I've got a couple of 6.5x47. It kinda depends on how far I want to shoot that day.

ajw308 said...

Contract kangaroo shooters? That sounds like some challenging fun. Can't beat getting paid to shoot. Any idea how much it pays?

Athor Pel said...

Nate,

Did you get the article I sent?

Allabaster said...

Ajw. The money mostly comes from selling the pelts and meat, from what I understand it is not as viable as it used to be and regulated to the point of insanity.