Here's an extreme example of what can happen when 'any old body' is allowed to design their own mould, cast their own bullets, and load for their own rifle...

Seen recently at a local auction house, high quality 20b Brit sporting rifle, raped.

I'll start with the bullet.

That's grams. Do the math..!

Now, this is a piece of brass found with the rifle.

That base was spool-shaped. Hourglass-shaped. Stretched. The belly bulged.

Nice rifle too, snap-action Lever-Under-Guard rotary.
Here's the action flat detail...

The only portion of the barrel-set to have seen recent polish was the flats, I wonder if they were trying to hide something..?

Grossly over-weight bullet, no effective grease groove to speak of, over size, and too hard...

Cheers
Tinker