Short Barrelled Rifling

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pingpong

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The thread on the NAA Mini revolvers got me to looking at my own 22 short NAA revolver and I noticed the barrel is rifled. My dumb question is "What's the point?" Could you notice a difference in accuracy in a 1 1/8" barrel in a gun that doesn't even have sights anyway? For you techies out there, is there a minimum barrel length(in any gun) where rifling gives diminishing returns?
 
well.. I am not extensively educated in this but a spiral is always more stable than a "duck" my guess it that, accuracy set aside (barrel length and lack of sites) the rifling is an attempt to optimize stability of the round... even in a 1 and 1/8 inch barrel.
 
I could be mistaken, but I'm pretty sure cartridge firing handguns are required to be rifled under the law, otherwise they're NFA weapons.
 
Yes. Without rifling to stabilize the bullet, it will begin to tumble immediately out of the barrel.

I don't know the math offhand, but generally speaking, there is a minimum barrel length to stabilize a bullet, dependent on bullet weight, shape and velocity, as well as twist rate. For the .22 LR, the 1.125" tube on the NAA's is long enough. OTOH, NAA built the mini's in .17 HMR for a short time, and the round was too fast to be stabilized in the 1-1/8" tube. I owned one, and it always keyholed the shots. NAA ended up replacing these .17 HMR guns with .22 magnums and included a .22 LR cylinder for the inconveniece.
 
is there a minimum barrel length(in any gun) where rifling gives diminishing returns?
Click to expand...

What "diminishing returns" would there be? If the intent of the gun is to shoot a elongated solid or jacketed round (rather than a shot shell for example) rifling improves the effectiveness of the bullet. Without rifling we'd still be shooting round balls of lead out of muskets. The spin stabilizes the bullet in flight, allows it to travel further and retain more energy over a longer distance as well as improves accuracy. The latter provided the rate of twist is proper for the weight bullet to be fired. All these things are pluses. There is no downside to rifling that I've heard tell of, well unless a fella's trying to make a barrel in his garage.

tipoc
 
With a Standard 1911 5" Bbl. in .45 ACP, since the chamber takes up at least 0.898 case length it's got approx. 4' of barrel length. With the very common to most handgun cartrdige twist rate of 1 turn in 16 inches, bullets only get a quarter twist to gain spin however that spin is at 850 FPS for
GI BAll ammo.

FWIW - heavier bullets perform better with a higher/quicker twist rate.
I've wondered besides the slide to frame fit on a CZ 75 does it's
1 turn in 9.7 inches help it's rep. as an accurate 9mm?

Randall
 
Muzzleloading rifled Deringers with a less-than-2-in. barrel have much better accuracy than smoothbore ones. I can only assume the same thing applies to cartridge weapons.
 
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