Talk:Rifling

Why right-hand spin

I seem to remember that there is a reason (more than just tradition) why modern rifling uses a right-hand spin. Anyone else remember?

And does anyone have a good picture down a barrel?Rossami 23:55 15 May 2003 (UTC)

- Agreed, a picture or diagram is definitely needed for this article. -lommer 23:49, 9 Apr 2004 (UTC)

I posted an image relevant to this "Riflilng " discussion. the image is titled "marlin 35 rem 2". --Rickochet 13:01, 9 July 2006 (UTC)

rifling twist

As far as I know, right hand twists are not used exclusively. I once had it explained to me, that it using left or right twist depended on which hemisphere of the earth the barrel would be used in. (i.e. left twists for southern hemisphere) and that the reason for this was to preferential compensation of the earths magnetic effect. I was told this by a guy who was a sniper, and he believed it, but I cannot say definitively whether its true or not.

If the hemisphere thing were true (which it isn't) then you'd also need a different twist for shooting east and west. Right hand is most common, but some makers, such as Colt and many British makes, use left hand. As for the sniper, I'll bet he wasn't actually a sniper; 99% of people who claim they are snipers and/or special forces are not. If you really want to test a the custom 1911 gunsmiths using it on bullseye guns, and why don't you see it in benchrest rifles, where accuracy (i.e. fractions of a minute of arc) is a realy concern?

There is some discussion as to why Pope used a left-hand twist in his barrels. I have the reference in front of me, but am unfamiliar with the best way of including this information. Additionally, it doesn't explain why many barrels are right-hand twist today.

Experiment

I'm dropping a ball, and hoping to get it to bounce straight back upwards. Would rifeling help to ensure it fell and returned dead straight? Larklight (talk) 15:32, 10 February 2008 (UTC)

Polygonal rifling to my knowledge can only be manufactured by Hammer forging method which is VERY expensive. It is more cost effective to broach or button rifle a custom barrel and then finish with a lapping process to remove as many imperfections as possible.

--Rickochet 13:16, 9 July 2006 (UTC)

Actually, hammer forged barrels are CHEAP, once you pay for the megabuck machine--that's why Ruger and other big makers use hammer forged barrels. The hammer forging process gives you get a rifled, profiled, and chambered barrel spit out of the machine every minute or so--about what it takes to broach or button rifle (but not profile) a barrel, and far, far less than a single point cut rifled barrel. You can buy polygonal barrel blanks (Lothar Walther: http://www.lothar-walther.de/html/363.php) but while Walther barrels are used by world class airgun shooters, traditional cut or button rifled barrels from makers like Krieger, Lilja and Shilen are still tops in the benchrest game. You can also make polygonal barrels with a broach or button, all you have to do is cut the tool accordingly. Cut rifled barrels are done in multiple passes, so that's the one technique that is really impractical for polygonal rifling. scot 15:44, 10 July 2006 (UTC)

• Leading is caused by high pressures (such as in magnum cartridges) or gas blowby on a poor seal between barrel and bullet, which cause melting of the lead. You can't claim that polygonal rifling seals better yet leads worse. My speculation is that the polygonal rifling doesn't grip the softer bullets as well, so accuracy will suffer.

scot 16:11, 31 May 2006 (UTC)

error?

"an220 Swift if the bullet was driven too fast.  The result was a blue-ish streak downrange as the bullet flew apart.

If you do some calculations, starting with a 3000 foot per second bullet in a 12 inch twist rifled

I have long suspected, but do not know for sure, that Sam'l Colt was left-handed.

The Single Action Army (SAA), of his design, seems to have been made for left-handed shooters, with the loading gate on the right, making reloading difficult for right handers.

It was possible to reload the SAA while shooting it, by leaving the loading gate open and as an empty came around to the ejection port, kick out the empty, put in a fresh cartridge, and continue firing, repeating this process as long as desired, without stopping to eject six empties and reload six loaded cartridges. This method is a lot easier for left-handed shooters than for right-handed ones.

I note and was somewhat surprised that my inexpensive knockoff of the Colt 1911 by Rock Island Arsenal, has a right-handed twist, more in line with "normal" practice.

I have a high suspicion that IF Mr. Colt was indeed left-handed, this may explain why all (as far as I know) Colt handguns have a left-hand twist, as opposed to most other firearms. It seems like it might just have been a whimsical preference of Mr. Colt to use left-handed rifling in his firearms.

I wonder if anyone knows for sure.

---

230RN

picture

The picture captioned "a tank's main gun is often rifled" - wouldn't it be great if the picture was of a tank with a rifled gun.87.102.123.108 19:18, 17 October 2007 (UTC)

The rifling in that picture looks pretty obvious to me...? Socrates2008 22:52, 17 October 2007 (UTC)

How does it actually work?

This article seems to lack on explanation on how the barrel being twisted makes the bullet spin. how do the grooves (or whatever they are) actually force the bullet to spin? in the first rifles they used leather patches wrapped around the bullet the make it grip the inside of the barrel. What's the modern equivalent?

There are a number of assumptions you're making in that question, which aren't really valid. First, "patched" bullets are still used in some modern firearms, but only to allow a significantly smaller diameter bullet to be fired, such as a .223 inch bullet from a .308 inch bore. These are called sabots, and are used in everything from small arms to shotgun slugs up to the main guns in tanks. They can be used in rifled or smoothbore barrels, though in a smoothbore you need an inherently stable projectile like a flechette.

Next, the patch in a muzzleloader really has nothing to do with rifling, because patched balls were used in smoothbores as well. Muzzleloading guns needed to have a loose enough fit you could ram a lead ball down the muzzle by hand, which meant that for, say, a .50 caliber rifle you used a .49 caliber ball, and filled up the remaining space with something squishy, like paper, cloth, or thin leather, that you could push down the bore easily. And remember that black powder is very inefficient, with about 60% of it's mass after burning ending up as solids, either particles of smoke, or crud deposited inside the bore. This just makes the gun harder to load for each successive shot, so from a military point of view, a really undersized ball with a thick patch was a positive thing, as it made reloading in battle faster and easier.

Last, not all muzzleloading firearms used patched balls. Look at the loading instructions for a cap and ball revolver, for example. A .44 caliber revolver uses a .45 inch ball, which is swaged into the chamber by a lever located beneath the barrel, which gives the shooter enough leverage to squish the oversized ball into the chamber, and provide a tight seal. Also, by the American Civil War, the Minié ball, with its hollow base, had largely supplanted the need for patched bullets. The hollow base of the bullet would expand with the pressure of firing, spreading out the base of the bullet to produce a tight seal with the bore, and engage the rifling so the bullet would spin.

Breach loading rifles typically use bullets sized to the groove diameter (the low spots), and the front of the chamber is cut to match this diameter so the bullet slips right in. The diameter at the lands (the high spots), is a few thousandths of an inch higher, and upon firing, the bullet travels along the open bit by the chamber, called the throat or freebore, until it hits the rifling. By this point, the pressure behind the bullet is on the order of 10,000 to 60,000 pounds per square inch. On the low end, say, a .22 Long Rifle, that's about 400 pounds of force pushing the bullet into the rifling, where it swages into shape. Look at a fired bullet, and you'll see the engraving, which is the image of the rifling impressed on the bullet by its travel down the barrel. scot (talk) 21:34, 18 August 2008 (UTC)