Your article regarding twist rates in the new Handloader is going to cause a lot of hurt feelings...

Great read.


Travis

I think I'm going to have "silly fad" etched into that new barrel.

Mr. Travis,

Thanks very much!

I lked the article. Well researched as always. E

That'd be a nice touch.


Travis

I called the local grocery store and they dont have it on the Magazine rack yet. Where can I read the article online?
Thanks
Craig

They come to my door.

I will never do the online thing. Reading on the schitter is a timeless tradition.


Travis

I havent seen it yet...What'd he say? What'd he say?

He said people that oppose fast twists can GFT.

(I'm paraphrasing)


Travis

I don't believe you...

JB - excellent article, as usual. I enjoy reading your articles as I always learn something new. Thanks.

He also said most guys that are not proponents of fast twist rifles tend to be 150+ years of age.


Travis

Well FYI...in a few short days Mr. Barsness will be the same age as me!

He just looks better at it...


Still don't believe you.

Humm, I've only been promoting fast twists since Moses had a paper route....

BS...you weren't there when Moses had a paper route...I was....

Fogie....

He said that old, slow-twist guys, like you, have stability anxiety.

I haven't bee 'stable' for a loooooooooong time...

Travis I have a laptop so I can still read on the chitter.
But like you I prefer the regular Magazine .
Craig

That's gross.


Travis

But if somebody knocks, can you throw your laptop against the door and scream "GFY!"?

Can you roll up your laptop and smack your dog?


Travis

What is a fast twist?

Respectfully,

A. Einstein

David Tubb and Methusala both figured out the same quite a while back.

You've both exposed yourselves (yes, I'm betting that's true as well) as liars in referring to it as a paper route. Having actually been there myself, I will point out that it was a tablet (as in stone) route. So there.

You're all wrong,rocks were not that big back then...pebbles only

Unstable = Too slow a twist likely.

GFY.


Travis

Ketel One, on the rocks, with a (fast) twist of lime...great way to stabilize at the end of the day.

Check with Chubby Checker about last summer.

I am guessing then that a gain twist would hep both problems; pressure and stability. Just guessing mind you. Cheers NC

My unqualified guess would be yes, but the only way to make a good gain twist is to hammer forge it like Steyr and FN are doing. These are about the most accurate factory barrels being produced, IME.

I would think it would be hard to remove the mandrel from a hammer forged gain twist.

Cut rifling, I would think, would be the best way to make a gain twist.

DF

But definately twisted, none the less....................

The title to the thread looked really interesting, but the rest is history............

JBs article prompted me to buy the magazine. Glad I did as it was a good article. Thanks Mr. Barsness.

Not to mention pressure is not an issue.



Travis

He said, at least impliedly ...that the 270 is just as good as the 7mm's and the 6.5's if you twist it faster and use the same type high BC bullets...

Well to be fair John didn't really say that....but his little captions near the pictures of 25 and 270 bullets sort of explain how 6.5's and 7mm's go to be so "superior" to 270's.

The article was excellent! And timely.


Side Note: Where did this utter ridiculousness about fast twists and higher pressure come from? Sounds like gain twist is a solution to a problem that never existed.The shooting world is loaded with those!

RinB and I (among others) were having fast twist cut rifle barrels built in 270,7mm,30,and 375 back in the 80's.It was old Bill Steigers of Bitterroot Bullet Company who educated us on this stuff, based on extensive work he did with them back then.The reasons were a bit different from those ordinarily proffered today.

Ahh, so you were the one with the paper route??

Something postulated by Chubby Checkers in the early 1960's

I hadn't the chance to read it, yet.

Did he mention anything about the results of testing fast twists on short bullets?

Like a 1:7 twist on a 40 gr .223?

smokepole I hate to admit it but I was well past paper route age in the 80's....

Good read, but incomplete. Needs a follow on piece to address the notion/rumor/fact of fast twist barrels significantly reducing barrel life.

Sorry Bob, I thought we were talking.......1880's.......

You guessed wrong twist has little to no effect on pressure. Ran the same ammo through a 14 twist 223 and a 7 twist with the same pressure mesurred. the twist effect pressure is an old wives tale that refuses to die

haha! It ain't easy getting older....

Yes. He said they shoot small groups.

And he also stated anybody that thinks barely stabilizing a bullet improves accuracy wouldn't be able to tell you if Jesus Christ was crucified, or died from the schitz.

(Paraphrasing again)


Travis

It is a proven fact, almost, that gain twist barrels not only reduce pressure by at least 85%, increase velocity by 115% and decrease group size by 63.06%, plus the more they get shot, the cleaner they get. And any caliber bullet can be used in any caliber barrel.

The twist is made by driving a six and one half rifeling cutter thru the barrel, heat said barrel to at least 683 degrees, clamp one end in your vise and twist the other end with a pipe wrench until desired twist is obtained in each end. Some even prefer the "reversing twist" over any other.

That is all the info I can share at this time but stay tuned. Jeff Zero and TRH will be along shortly to continue.

BigBuck, that is all just common sense.

What did you get me for Christmas?


Travis

Beer. When you coming to drink it?

Next summer. Or this Saturday. Not sure yet.


Travis

Sookum! Thank ya, sir.

Damn JB., had this twist business all figured out until you stated throwing in facts.

Did he say anything about bullets blowing up before they hit the target in fast twist rifles. I have it on good authority that this happens all the time.

I've seen that myself, but it mostly depends on the bullet, not the twist, plus the temperature of the barrel. Put a soft-cored, thin-jacketed bullet through a fast-twist barrel, especially if the barrel's hot, and they will come apart, or at least go off in weird directions.

On the other hand, varmint bullets will explode better on prairie dogs from a fast-twist barrel. Last summer I shot side-by-side with a friend. We were using the same 55-grain bullet, but he was shooting a 1-8 twist .223 and I was shooting a 1-14 twist .220 Swift. The difference in muzzle velocity was around 700 fps, but the .223 exploded dogs noticeably more violently than the Swift.

I didn't mention that in the article, or thin-jacketed bullets coming part, because the article was about bullet stabilization, and there is only so much space in a magazine. I chose to use it on stabilization, trajectory and accuracy--though I have mentioned the other stuff in other articles.

I have had the SX bullets come apart in a 1-9" .223.

I bought a bunch of those 55grainers that Nosler had on clearance and they did not do well in a 1-8" 22-250 when pushed hard.

But then again, those bullets aren't really made to be pushed hard anyway.


Travis

Well said, as usual....

Mr. Travis,

Thanks much for the information.

The weirdest one I've seen was with the then-new "afforable" Winchester factory ammo with the 45-grain jacketed hollow-point. The core is very soft, the jacket thin, and the same bullet is loaded in .223 and .22-250.

A friend and I were shooting PD's one say in western Kansas, when the temp was at least 100. All of a sudden he couldn't hit schidt, and he's a good shot. Meanwhile I was doing fine with a .223.

Eventually we set up an empty cardboard box with a target pasted on it. His first two shots were spot-in, but the next was off by an inch, and the next two were even farther off, with a spray of lead core around the holes. Major melt-down!

That was the same shoot where he set the forend on fire, and we had to dunk it in a big cooler of ice and water....

Loaded some SX 50grn in 22-250. Shot just fine in my "22 1-12. Buddies Savage "28 1-9, grey dust.

I've seen it too, thin jackets and soft cores with fast twist... The funny thing about that is that some guys act as if there has never been a bullet to reach the target from anything more than a 1:9.

Is this a euphemism for something?

The 55gr SPSX would blow up on 4 out of every 5 shots at 3750fps from my .22-250 with 12" twist. If I slowed them down to 3600fps, not a single blow up. That was obviously the razor's edge of where that particular bullet could hold together.

Beer coolers are good that for that...


Travis

Yeah, they come unglued (regardless of twist) when you really push them. I'm pretty sure Hornady doesn't recommend them past 3,400fps.

The only other bullets I've had behave like that were some Nosler seconds. Nosler told me they were bleed overs from a bullet they made for the Australian market. Wicked accurate, just too thin jacketed for the fast twist, high velocity rounds.


Travis

Bet they'd be happy to.

Who would be happy to? Do you have a link? I'm getting "Dong Kong" on my next tube.


Travis

My gunsmiths have been using Krieger 1:8 twist barrels on their .30 cal. long range rifles for years. The results of a 200gr Matchking on deer, elk, bear, and moose have sold many rifles by word-of-mouth, as well as repeat customers.

A 1 in 11 308 with 175 Sierras is an accurate combo. I have no idea what would be optimum for say, 190gr Bergers from a 300 win mag. Any ideas, anyone?

The standard .30-caliber 1-10 twist is plenty for any high-BC lead-cored bullet up to 210-215 grains.

Above that and a faster twist might be needed under certain conditions, but Berger even lists their 230-grain bullets as OK in a 1-10 under most conditions.

Thx MD, I'm pondering a heavy-barreled (with a Fat Bastard brake) 30cal mag

FWIW:

Best ballistic stunt I ever saw was a 22 hornet boolet (36 grains?) driven over 4,000 fps in a 220 swift (from a Ruger #1 varmint rifle).

It "puffed" at about 30 yards and completely disappeared. Not a mark on the target.

As for twist, faster is better.

Also, Travis-GFY.

BMT

Thanks friend.


Travis

You never thank me...

Thanks friend.


Travis

Dats more like it....

I'll leave you my 66 now.

Y'all grow 'maters in Montana too?

nope. just 'mah-ters.

Pulled some bullets in my 300 WBY, 200gr with too much 7828ssc. Installed 110 round nose 30 carbine bullets. Did not chronograph, but they made it 100 yrd to paper. 1 1/4 group, grey dust behind paper. Plan to load some more and try it on a squirrel some time.

You just have to limit your woodchuck shots to 30 yards and let the shrapnel kill them.

Flechette round...............

The 8 twist gives the 200gr bullets greater rotational velocity, with an effect similar to what you saw with the fast twist .223 vs. standard twist Swift. (Except elk don't really blow up.) They're working on a fast twist .338/.378 for the 300gr Matchkings.

Just picked up the mag, just to read this dang article!

Long time reader, short time poster here. Just thought I'd chime in with my $0.02. I think the reason people get stuck on pressure so much is because it just makes sense. People figure:

faster twist = harder to push a bullet = higher pressure

It also makes sense that pressure will be higher if you think about it from the perspective of energy. The energy of a bullet is equal to it kinetic energy plus it rotational energy. So a bullet fired from a 1:8 twist 223 at the same velocity of as a bullet that comes out of a 1:12 twist 223 will have more total energy because it is spinning faster. How does it get more energy? The only way is to increase the work done on the bullet. Work = force x distance, and the force on the bullet comes from pressure. Obviously pressure isn't constant as a bullet moves down the barrel, but in general you have to increase the average pressure to increase velocity.

With all these thoughts swirling in my head I thought I'd run some numbers. A 55 grain bullet at 3300 fps will have about 1330 ft-lb of kinetic energy. At that velocity a 1:12 twist bullet will spin at 3300 rev/s and a 1:8 twist bullet will spin at 4950 rev/s. Rotational energy is 1/2 x moment of inertia x angular velocity^2. For simplicity I calculated a moment of inertia for a cylindrical shape. After plugging everything and making a few units conversions I got the following:

1:8 twist rotational energy = 5.1 ft-lb
1:12 twist rotational energy = 2.3 ft-lb

Pretty much negligible compared to 1330 ft-lb. If your gun has 22 in barrel, the extra force on the bullet to get that extra 2.8 ft-lb of energy is 1.6 lb. It takes 124 psi on the back of a 0.224-in diameter bullet to get that force. Again, it's important to note I'm talking about the average increase over the length of the barrel and not an increase in peak pressure. Also, due to inefficiency, I would guess the actual increase in pressure to be somewhat higher. Still, even if the increase is on the order of 500 psi the change is less than 1% of 60,000 psi. Somebody with more experience than me can chime in, but I would have to wonder if a strain gauge on a pressure barrel would even catch that.

Long story short. The idea of fast twist = higher pressure makes sense intuitively, but the numbers don't add up.

PS Feel free to double check math, this was a rush job.

Doesn't take near the energy to spin a bullet as it does to accelerate or push it through air. And if it won't spin in the barrel, it will just rip the jacket off. No ballistic lab to back me up, but makes sense if you turn one in your fingers, throw it in the air, or take a pare of pliers to it. FWIW.....my .02�

How should one go about breaking in a fast twist barrel?

Shoot it....

Spit on your pinky and put it in the chamber.


Travis

Good post, but that's because I like math.

Firth,

If you continue to provide accurate data and analysis, and good common sense, you will probably be in trouble here.

You will be messing with the minds of the totally convinced who have no basis for their convictions, but feel very strongly about them.

I'm waiting for someone to chime in and say that your data would be different if a rifle has a left hand twist instead of a right hand twist.

Steve

The angular velocity vector would point the other way.

And what about the Coriolis effect???

Can you get those in the leopard skin pattern...?

DF

You're getting dangerously close to the cornholius effect.

Now, dats a good one!

The Swedish judge gives it an 7.8 plus one bonus point for taking a poke at Ingwe!

Errrr... wait, in light of the topic of discussion and that Ingwe is involved, my phrase "taking a poke at Ingwe" does not sound quite right either!

John

Firth,

When it comes to guns and stuff, the guys who posted after I did really do know what they are talking about.

The other extraneous issues they brought up are just plain funny.

But in any event, welcome to the Fire.

Steve

I should have thanked Firth for taking the time to quantitatively make the point. When this subject was hashed a while back I did a similar calculation which indicated, to me at least, the differences in angular KE ought to be lost in the noise.

A little late to the party, but good post, Firth.

Nice when people take the time to quantify a few things and squash old wives tales with facts.

They tried that in the Carcano.

nice post, but I prefer guessing and feelings.

I'll bet you will get GFY shorty....just sayin'

I can't remember when but I seem to remember an article years ago that said that gain twist actually caused more problems than it solved because once the bullet engaged the rifling the metal will be displaced by the changing angles of the lands cutting across the surface of the bullet.