How many consider the 10mm a good option for deer hunting with a handgun?
I wouldn't consider it a "good option" where there are so many better ones available. I'm sure it would be fine. Those that consider the 10 to be "about the same as a 41 Mag." are wrong. The 41 will always hold more powder than the 10 and always be more powerful, all things equal. In the real world, things are never equal though and it is a nice round for a manageable sized semi-auto. No doubt the 40 would do fine too. I've got pistols in 45 Colt, 44 Mag., 41 Mag., and 44-40 in my safe that would all best the 10...not that they're necessarily even needed. I'm sure you've got most, if not all, of these as well. In reality, the 10 is about like a 357 Mag. which many think is too light for deer, especially if the aforementioned are available. I think the 357 is fine too.
It's just whatever one wants to use or has to.
