In my GM barrel, the top band engraved heavily, then the tapered slug engraved less, to the bottom band that was bore sized. This happened exactly the same on both bullet weights in .45 cal.
These slugs being shorter than the TC maxi-balls, may not only shoot better, but maintain better stability after impacting with moose and elk.
The maxi-balls failed miserably in this in .50 and .54 calibers up here in the special weapons hunt.
After we got the guys to switch to round balls, they were killing moose with one shot.
With the maxi-balls 3 or more shots were necessary, when they could catch up. Generally, they were shooting 3 or more moose to get one kill with those dang bullets.
I got sick of hearing at lunch time about the morning hunt, "I got "Maxi's" into 3 of them but they ran off. There was hair but no blood. I must have just creased them".