Not trying to be disrespectful.
One thing I've noticed in a lot of great shooters is that their grip is surprisingly strong for their size. When you are shooting fast, or heavy recoiling guns I find grip strength and aggressiveness helps in management of recoil.
Depending on your age and fitness level I would recommend starting to deadlift. Not only will it work on your grip, it strengthens everything else as well from your shoulders to your calves.
I understand that Jerry Miculek is probably not a powerlifter in his spare time but he has decades of shooting everyday.