.....really, REALLY, not sure where to ask this, but as it could be a wildcat for either a rifle or handgun, I'll put it here.....does a cartridge to be used in a revolver have to have parallel sides ?

Roger

No
There are many examples of tapered and bottle neck cases used in revolvers.
32-20
30 Carbine
38-40.

M

nope -- though rimmed is better

The problem is that pressure pushes on the sides of the case and the case wants to go in the direction that increases its space. If the sides are parallel the push is straight out so the case doesn't want to slide in any direction. However, if there is a taper, the case will want to slide in the direction that allows for an increase. since the taper is larger at the rear of the case, the case pushes back. the result is cases pushing back against the revolver frame. The 22 Jet was a good example of this. Any lube on the cylinder walls would aggravate the sliding and could lock-up the cylinder, preventing it from turning.

Sorry, had a bit of a brain fart there, all I could think of was 357,41 and 44 mag.
Hopefully a very slight taper, maybe a couple of degrees, wont create problems.

Roger

I believe Taurus made a revolver in .22 Hornet. I don't know how it worked out though.

Hip

I would suggest that it depends on what pistol you intend to shoot it in, auto or revolver..A revolver requires a rim so either will work. Most popular autos are straight and rimless as I recall, maybe an exception but don't recall any.

Auto cartridge with a bottle necked case - 357 Sig.

For us old Bullseye shooters, the common bottle necked, auto pistol, wildcat was the 38/45 Clerke.

I think the Tauras Hornet revolver has a front and rear lock up of the cylinder. Not sure if that reduces flex and stretch or not. Reviews I've read of it were positive.

Revolvers firing RIMMED cartridges is NOT an absolute: http://dailycaller.com/2016/11...tests-9mm-revolvers/

Well if you must get technical there are no actual straight sided cases that I can think off off hand, althought many are referred to being straight walled because the taper is minute..

Two have straight, parallel walls...the 500 Special and the 500 S&W Mag...0.530" at the mouth and 0.530" at the base above the extractor groove.

Not sure of any others.

AS long as the chamber has some kind of a small clearance to allow expansion to release the bullet, the spring of the brass will allow the case to be released from the chamber walls...UNLESS the pressure is above the deformation point of the brass, then you start having extraction problems just like any other "killed" case...then you probably will need a ram rod to "get the brass" out.

This question is definitely NOT a straight forward, simplistic, "one answer to it" kind of a deal...as there are way to many variables involved.

LUCK

It is a matter of pressure; for example the 38-40 is a quite pronounced bottlenecked case, and works fine in revolvers. But the example of Rays above, the 22 Jet, did not work due to the reasons he said.
And there are others that have to follow the rule.
Also, plenty of rimless revolver cartridges too; 45 ACP, 9mm, 40 S&W (I built that one). etc.

a straight peg will come out of a tapered hole -- just saying