I have no intention of getting rid of all my modern guns. I do hunt mostly with my BP guns. However, I practice much more mith my modern ones, so I can get in more practice. In shotgunning, I think its important to shoot often to keep up skills to hit moving( flying ) targets. If I was only using a shotgun to shoot turkeys, I could skip this. I use shotguns, including my ML to hunt pheasants, chukkar, and rabbits. If I ever get down to where they have decent quail numbers to hunt, I will use my ML shotgun to hunt those. I have used my modern shotgun to hunt dove, only because this tends to be a group activity, and not all the other hunters want me blasting the sky with my BP shotgun loads. It bothers them to see all the smoke, when they are wearing camo to keep from being seen.
As to handguns and rifles, I do like to keep my skills up with those guns, and that takes lot of shooting practice. I get more shooting in with my limited range time, if I take along my modern guns.
I challenge myself by reducing the size of targets I am shooting, or shooting at targets further away. Plinking beer cans at 50 yds with a .22 handgun is a challenge, but it really gets to be interesting at 100 yds. When I happen to go back and shoot a centerfire PPC course, limited to 25 yds, my scores always rise. I am usually shooting in the 460s( out of 480) without spending hours practicing for just that particular shoot. If I ever spend the week before such a match actually practicing, I suspect my scores will climb into the 470s. That would really shake up the other shooters who know me only as a " lawyer ".
If I did not have a .22 rifle, I would not get much practice shooting a rifle around here. Its too flat to fire a high power rifle safely, because its difficult to find a natural backstop, unless its at fairly close range along a river. I can pop shotgun hulls off a log at some distance, and when I get settled in with the gun, change to shooting .22 casings. Or bottle caps, then the casings. And, if I can put up a Target, do that old exercise where you turn it around and shoot at the back of it, using your first shot's hole in the paper as your aiming reference, and see how small a group you can shoot. Then turn the paper around and score it, using the target rings to show how close to center you hit. Very good practice, particularly with Off-hand shooting.