super short (mouse gun) barrels and rifling

simonrichter

New member
given the short engagement distance they are intended for and the minuscule barrel length: Would it make a real difference for a mouse gun (of, let's say a barrel length of clearly less than 2''9) if it had no rifling at all?
 
Very short barrels still spin the bullet, giving it the stability needed to avoid tumbling. Even a fairly small level of rifling works pretty well.
 
given the short engagement distance they are intended for and the minuscule barrel length: Would it make a real difference for a mouse gun (of, let's say a barrel length of clearly less than 2''9) if it had no rifling at all?

I see you are in Austria, but here in the US, it makes it a short barreled shotgun which falls under an entirely different legal classification.

As far as performance, it would be interesting to see if a spinning bullet has better penetration than one that is not. I've never seen testing on that.
 
Minor correction...

TimSr said:
I see you are in Austria, but here in the US, it makes it a short barreled shotgun which falls under an entirely different legal classification.
Actually, the NFA defines a shotgun as a shoulder weapon, so a mouse gun or derringer cannot be a shotgun. Per 26 USC § 5845(d), my emphasis underlined:
The term ‘‘shotgun’’ means a weapon designed or redesigned, made or remade, and intended to be fired from the shoulder and designed or redesigned...
A smoothbore handgun is an Any Other Weapon per 26 USC § 5845(e):
The term ‘‘any other weapon’’ means any weapon or device capable of being concealed on the person from which a shot can be discharged through the energy of an explosive, a pistol or revolver having a barrel with a smooth bore designed or redesigned to fire a fixed shotgun shell... Such term shall not include a pistol or a revolver having a rifled bore, or rifled bores, or weapons designed, made, or intended to be fired from the shoulder and not capable of firing fixed ammunition.
It is correct to note, however, that this is of no consequence in countries where there is no law directly analogous to the NFA.
 
All that is needed to spin the projectile is a short stretch of rifling; the spinning will continue on its own momentum regardless of barrel length.

But spinning the bullet is done for stability (and hence, range and accuracy). At short range, let's say 3 meters, the effect of a bullet would be the same, whether it is spinning or not. The idea that a bullet does damage because it "drills" into the target is a myth; in a distance of, say, 30 cm, a bullet would rotate only one time, not enough for the "spin" to have any real effect.

Jim
 
James K said:
...spinning the bullet is done for stability (and hence, range and accuracy).
This is particularly important for projectiles that aren't round, as a non-finned elongated projectile without spin stabilization will typically begin to yaw or tumble within a few yards of the muzzle, greatly compromising aerodynamic efficiency and terminal effectiveness.

Hence, traditional smoothbore single-projectile firearms such as muskets were generally only used for firing round balls, and even then their accuracy was compromised because the non-stabilized projectiles were easily deflected by wind gusts and vegetation. Round balls have very poor aerodynamics, so this limits such firearms to short effective ranges.

[EDIT: Guess I need to do more research into how slugs work.]
 
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Modern shotgun slugs overcome this by having a forward-weighted projectile-very much like a lawn dart.
"Rifled" slugs don't spin.
 
A couple points. Some shotguns with interchangeable chokes can have rifled choke tubes installed, and the two inches of rifling will spin a slug. English paradox guns had short rifled sections at the muzzle as well.

https://en.wikipedia.org/wiki/Paradox_gun

To remove the gyroscope spin of a bullet can cause that slug yo keyhole, tumbling within a few feet of leaving the bore. From what I have seen, a smooth bored gun would not allow a bullet to remain stable and you will have it flying through tissues like a drunken parrot, and maybe ending up backwards. Marie that doesn't matter for a .25,but anything more powerful will lose a great deal in performance.
 
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