Could this stop or dramatically slow down a bullet?

[Elite Engineer]

Could a sudden re-direction of rifling in a rifle barrel alter the velocity of a bullet? Some manufacturers have rifle boring in a right spiral, while other a left. What if half way

 

through the barrel there was a right spiral then an immediate left spiral down the rest of the barrel. Would this sudden change in direction dramatically slow down the

 

bullet...I doubt stop, but probably really effect its velocity.

 

~EE

[Phi for All]

I think it would negate the spin that normal rifling imparts, which could cause the bullet to tumble or otherwise lose accuracy. I'm not sure that would also mean slowing it down dramatically.

[swansont]

It's friction and the rotational KE it has comes from the linear motion KE. So it will slow down, but how much depends on the details.

[John Cuthber]

Why not simply use less propellant?

Or, given the way the OP is phrased, simply not have an opening at the end of the barrel?

[Elite Engineer]

Why not simply use less propellant?

Or, given the way the OP is phrased, simply not have an opening at the end of the barrel?

Simply curiosity, not practicality. In that case, I'd just give the fellow a blank

[J.C.MacSwell]

It would certainly increase the friction (and wear) of the barrel, and reduce the rifling effect It should slow it down.

 

Some rifles have twist gain down the barrel. I suspect if from the halfway point the twist was abruptly reversed the bullet might not manage to change spins.