ok,black powder shotgun,12 gauge but with an inside bore diameter of .70, ive got the 2.5" shells loaded with veg Crisco lubed .69/730 grain weight forward minies and loads from 70 to 120 grains of FFg equivalent.
How much range you think ill get before they keyhole?

*im asking because I am not able to just go shoot where I live.

Any advice would be appreciated,such as best charge,lube,etc.

You're pretty HOT at 120 gr,

I'd back down offa' that a bit, PARTICULARLY in an old gun.

GTC

Part of the equation is the shape/length/ thickness of the minies skirt and the overall shape of the projectile. To a certain extent, the weight-forward design will keep it nose-first until gravity drags it into the ground.


I'd listen to Greg. Google the drams to grains conversion rate and check your loads. Also, check out the usual loads for shotgun slugs, they are nowhere near the weight of your minie.

Shotguns are proofed for much lower pressures than rifles and even a newer shotgun will not be proofed for rifle pressure loads. If you are using an old gun, the pressures are even more critical. You have no idea of the guns past and if it has been over-pressured, setting yourself up for disaster.


As to your original question, the only way to know if a particular projectile is keyholing is to shoot it.

Ed