Rifling - Right v Left twist

iceracerx

I attended a long range rifle clinic today and one instructor claimed that 'most' rifling is right twist. I seem to recall that my Colt pistols have a left hand twist and Sharps rifles and Pope barrels did also (ok, I'm old and like history).

Do MOST (rifled) barrels have right hand twist?

Is there a benefit to either type?

Would nononsense or someone point me to an information source?

Thanks.

Ray B

Yes, most guns have a "right hand" twist, meaning relative to the shooter the bullet spins in a clockwise direction. When I was in bootcamp about a hundred years ago we were told that the Colt 1911 had a left hand, counterclockwise spin- the reason being something to do with counteracting the gun being held in the right hand. Personally, while the theory made for talk in the class, I don't believe it. There is some drift due to the spin, but this is only noticeable at really long range- nothing a 45 ACP is ever going to experience.

tsr1965

The main reason that some barrels are left twist, is to counteract the torque, applied to the barrels thread interface to the frame, when the bullet travels down the barrel. You see, those barrels with left twist, are threaded in the revrse direction, of barrels with the right hand twist. It is done, so the barrel does not unscrew itself from the frame, after hundreds, or thousands of rounds fired.

I am sure Nononsense will give you additional information.

Best

Tailgunner1954

D
Like lug nut threads (and positive ground battery systems), there is a lot of theories on why to choose one over the other.
But it's just that, theory.
Out in the real world, it really doesn't matter as they both work equally well.
JMHO of course [:D]

nononsense

iceracerx,

Over the last 150+ years there have been numerous attempts to demonstrate or disprove that the direction of rifling has benefits for the shooter. The greatest selection of Left Hand twist has been in the semi-auto pistol world. The rifle world experienced the left/right debate when the Brits and Canadians tried to use the rational of the left twist pulling the rifle away from the shooters cheek, thereby sparing him or her from the pain of the recoil into the face. This did not diminish the recoil to the shoulder though. The American rifle industry did experiment with Left Hand rifling as well but has since returned to the Right Hand rifling as a standard.

Originally, the thinking was to use the LH rifling as a tool to counter the torque of the semi-auto pistols, causing the pistol to move into the palm of the RH shooter. I think that most of shoot and compensate through muscle memory when it comes to controlling a pistol.

Several years ago we experimented once again with the left hand twist in rifle barrels for the larger calibers used for hunting in Africa. We made a few barrels in different calibers then chambered them for specific cartridges known to produce heavy recoil.The stocks were designed to minimize recoil, staying within the accepted parameters of design for the firearm. In short, the effect was minor when compared to the rearward recoil from these cartridges. The shooters including myself experienced the 'up and back' force as opposed to the 'away from the cheek' effect suggested by the British.

Textbook of Pistols and Revolvers by Hatcher; page 144:

"The usual American practice is to make the rifling with a right handed twist, and all American made arms except the Colt pistols and revolvers have right handed rifling. Colt guns, on the contrary all have the rifling left handed, which is the English practice. The reason for this is that after the failure of Col. Colt's first factory in America, he went to London and made his revolvers there for some years; and as the rifling machines in use there were adapted for a left hand twist, Colt used it, and the Colt guns have been made the same way ever since."

Examples:

(Snippets collected from various sources)

By choosing to rifle the bore either with right hand twist or left hand twist rifling, the designer can choose to have the rifle stock twist into the shooters face or twist away from their face. By convention, the British chose to have the rifling of their large bore rifles cause the stock (remember Mr Newtons laws here) to move away from the shooters face, rather than twist into their cheekbones. The recoil energy transmitted to the users shoulder remains the same in both cases.

Interestingly, many American makers at the turn of the century made barrels with a twist opposite to the "standard" British pattern, thereby causing their customers to directly experience a triumph of fashion over physics.

1. The left hand twist offsets the direction the barrel is screwed into the frame. Supposedly, according to this theory, that is why Smith & Wesson revolvers have the barrels pinned, but Colts do not.

2. Another theory is that the left hand twist in Colts revolvers causes the downrange bullet drift to offset the natural tendency of a right-handed shooter to pull shots to the right.

The fact is that Samuel Colt was left handed, and you can see the legacy of this in many Colts firearms. For instance, the Single Action Army is clearly intended for left handed operation (even tho Col. Colt was long dead by then): The weapon is held in the left hand and the loading gate is on the right. So, it seems to me that the twist of Colts revolvers could be more due to the handedness of the company's founder.

Strange? Consider that British autos, and often the nations that were in their empire or closely associated with them (like Japan) at the turn of the century are right hand drive. I understand that the reason for this was that jousting took place, along with wielding a sword, generally with the right hand. So, jousters passed on the each other on the right sides and the left hand was free (presumably to handle the shift lever).

Still, the list of nations that chose left hand rifling twist is interesting: Norway became independent in 1905 from Sweden and was closely aligned with the UK thru royal marriage. (King Haakon VII was married to Queen Maud, who was Britain's King Edward VII's daughter.)

Discounting Britain and British influence, France's choice of left hand rifling is interesting. French engineering often chooses solutions that do not appear like the solutions of other nations, but are often quite rational and workable.


Ross M10 MkIII .303 British (1916) - Left Hand Twist
Colt 1851 Navy - left hand gain twist rifling
The 1860 Army - right hand twist rifling, also gain twist

Best.

iceracerx

Thanks for all the great info. Nice to see information from Hatcher!

As a 'southpaw', I've been experiencing recoil (torque) my whole life contrary to what all you 'righties' have.

Rifling twist might explain why I enjoyed shooting a 338 Lapua Mag (I only noticed rearward recoil) and my right handed buddies didn't.

PS nononsense, I'm waiting for your thread on "What is Recoil and how is it Calculated."

http://forums.gunbroker.com/topic.asp?TOPIC_ID=195420

machine gun moran

A little off-thread, but I have to disagree that Sam Colt designed his guns for left-handed shooters because he was left-handed himself. Colt was one of the time's best marketers and promoters, and he knew that 90% of his market was right-handed. The percussion guns were apparently designed to be held in the left hand while being capped with the right hand, because that's where the dexterity was. The system seems to have followed through when Colt engineers developed the Open-Top and the M1873. [:)]

Cheechako

If you ask a barrel maker why some of his barrels are left twist, he will tell you:

1. To even out the wear on my machinery.

2. Because a customer wants it.

Number 2 is the answer to most questions asked of any manufacturer, not just barrel makers. Why are most Oreo cookies dark on both top and bottom? See #2.

JMHO

Ray