Why dont we worry abour gas cutting with round balls?

[cpileri]

or do we?
I know we all try to make nice squared off cases for the cast bullet. (Or a gas check), and throw the rounded ones back in the pot.

At least , seems like we mostly do that.

but then we have threads extolling the virtues of round balls: the ultimate round based bullet! is it because they are loaded to lower velocities? or have wadding to support them? or because a rounded base is off-balanced and will shoot poorly which doesnt happen to a round ball which is symmetrically round? or am i missing something?

C-

[btroj]

Patched Rounds balls give good accuracy. The patch grips the rifling and the ball, it also seals the bore.
Too thin a patch, wrong material, or other factors can lead to cutting the patch which can affect accuracy.

[longbow]

If you are meaning round ball loaded into brass cartridges then in most cases the loads used are very light so very low pressure. If you push a round ball it will likely also gas cut. It may strip in the rifling first due to small driving surface too.

The hottest load I have put under a round ball in my .44 is 10 grs. of Win 452AA (old shotgun powder). That worked pretty well and accuracy was good.

Round bases on boolits are more of an issue with accuracy than gas cutting assuming the rest of the driving bands have filled out reasonably well.

My take anyway.

Longbow

[Chicken Thief]

Rounding on a boolits base is uneven around the circunfense thus gasses will push the boolit uneven when it leaves the crown.
On a round ball the "edge" is even despite it being ultimatly rounded.

As to speed, think of the small/narrow "equator" band that will transfer rotational energy to the boolit and, it is evident that it will take little force before it strips.

[cpileri]

I guess i was thinking round balls in brass cases. Should have been more descriptive.
but all y'alls answers make sense.
Low velocity/low pressure seems to be the key w rbs. And an off-balance boolit isnt worth shooting, accuracy wise.

makes sense to me.
Thanks!

C-

[btroj]

It isn't so much off balance. A bullet with an EVEN round base can shoot well. The base of the bullet is the last thing to leave the crown. As it leaves the powder gases are rapidly following it. If the base is slightly different on one side than the other the gases can escape sooner on one side and impart a side force to the bullet. This makes the bullet slightly less stable and will open up groups. Same thing as a damaged crown.
Key is making very concentric bullet bases. Much easier to do if they are square than if they are rounded. Out of square is easier for the eye to notice than slight differences in the rounded base.

It isn't shape, it is making the base consistant and concentric.

[popper]

Proof - I cut the base of several and they formed a nice 2" 'ring' around POA, uncut hit the POA. I didn't remove much metal. I've flat based all my moulds now so I can see the bad bases - they go back into the pot. I have to bell the cases a bit more but targets look way better.

[rond]

It isn't so much off balance. A bullet with an EVEN round base can shoot well. The base of the bullet is the last thing to leave the crown. As it leaves the powder gases are rapidly following it. If the base is slightly different on one side than the other the gases can escape sooner on one side and impart a side force to the bullet. This makes the bullet slightly less stable and will open up groups. Same thing as a damaged crown.
Key is making very concentric bullet bases. Much easier to do if they are square than if they are rounded. Out of square is easier for the eye to notice than slight differences in the rounded base.

It isn't shape, it is making the base consistant and concentric.

I can see how a bad crown can push the boolit at an angle but if the boolit is spinning at a very high rpm I don't see how a blemish at the base will cause that much of a problem. I have recovered boolits with rifleing marks all the way to the base of the boolit.

[BABore]

I can see how a bad crown can push the boolit at an angle but if the boolit is spinning at a very high rpm I don't see how a blemish at the base will cause that much of a problem. I have recovered boolits with rifleing marks all the way to the base of the boolit.

They get that as soon as the boolits base is fully into the rifling, not at the crown. An uneven base allows gas to escape the barrel unevenly. This affects the boolit stability which gets exaggerated by the RPM's

[btroj]

Those rifling marks need to be even too.
Try cutting a notch or other blemish into the base of some bullets. Try shooting a few groups comparing flawed bases vs perfect bases.

The base is the steering end of the bullet. If it isn't perfect then it isn't worth shooting.

[geargnasher]

Stripping a round ball is difficult to do, even when fired out of a cartridge. It has just about the lowest static inertia of any projectile shape that can be launched, and since most of the mass is in the middle and not at the edges gripping the rifling, yanking it into a spin is a relatively low-stress endeavor. Make them soft and keep the pressure up the whole trip through the barrel and you're good to go.

Gear

[nvbirdman]

I would say the flame temperature is probably too low to cause gas cutting.