An odd rifling question

L

Long Beard

Inactive
My brother is into air-powered rifles, among his many other traditional arms. What he showed me, which I've never seen or heard of, is that the rifle bore is smooth except for about an inch, inch and half at the business end. The reason, as he explained, was to maximize bullet velocity and energy. Thinking about the physics aspect, rifling increases drag. The more, and longer, the rifling the more both are lost. The question now is, would this same concept work in a cartrage fired rifle?

Shooting that 30 caliber full-auto is a blast. Too bad it only holds 16 rounds. As soon as the shop gets one in, he's buying the .50 caliber.
 
If it didn't just strip in the rifling.

My guess is that the air rifle's muzzle velocity is pretty low, so when the projectile hits the rifling, it's not going super fast.

If it were going really fast when it hit the rifling, the tendency would be for the projectile material to just fail and strip off in the rifling without imparting much spin to the projectile.
 
I hadn't heard of it on an air rifle, but Colonel Fosbery (Yes, that Fosbery) designed the Paradox gun with a few inches of rifling at the muzzle. This gave a gun that would shoot solid slugs with reasonable accuracy and shot with a pretty good pattern. Lighter than a "gauge rifle", more powerful than a shotgun, it would be very handy if you wanted to travel light and shoot anything that walks, crawls, or flies.
Holland and Holland will still make you one for $183,000 at the current exchange rate.
https://www.hollandandholland.com/the-paradox-gun

I understand that match spring-air rifles are fully rifled but are choked a bit, to build pressure and velocity.
 
Would it work in a cartridge rifle? Sure it would.
The Brits did it 140 years ago. Paradox gun.

"Put simply, a Paradox Gun is a shotgun with a partially rifled barrel that enables it to shoot both slugs and shot with reasonable accuracy. Colonel G.V. Fosbery first developed what we now call the Paradox Gun back in the 1880s by adding a small amount of rifling to the choke on a shotgun."
 
I recall reading but not where, that rifling was original a shotgun thing that they hoped would cause the shot to spread more in close range. As I recall it didn't work for that but someone figured out it along the way it would stabilize a bullet in flight. Or so the story goes anyway. Take it with a gain of salt...

Tony
 
Rifling is one of the more costly operations in building a rifle barrel, so restricting the process to the few final inches of the bore would be a cost-saver. In a cheap air rifle, that's probably the reason. I owned a RWS 48 years ago, and it was fully rifled. Pressure expands the pellet skirt into the rifling, sealing the bore and better utilizing the pressure available. In a cheap air rifle, I suppose making a Paradox type of bore would offer several savings.

Yes, rifling adds friction, but in a cartridge rifle that friction helps the pressure rise and burn powder more efficiently. Roy Weatherby famously cut very long throats on his high-dollar rilfes to gain velocity without the initial drag of the rifling and also keeping his pressures lower.
 
The main reason is probably velocity. most air rifles are subsonic. and the pellets are generally light enough that they would start rotating easily when the rifling started due to their low mass.
 
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