I know most will say why not just go with a .45, but then again, why not a 10?
I had this thought tonight. Was at LGS tonight and he had a used unfired Glock 20 with Tupperware case and 2 mags for $400.
I almost made an impulse buy.
I currently carry a Glock 41 uniformed and Glock 30S off duty. Both are 45 ACP. I use the 30S for most hikes and road trips, etc. It's my daily carry. I also handload 45 ACP 230 grain ball like the Gubmint hands out food stamps. You could say I'm deep into 45 ACP.
So I called my friendly Tackleberry-esque co-worker and asked about the 10mm. Be raved about it for hiking, especially with Gucci hunting ammo from Doubletap or Underwood. I asked whether 10mm offers performance sufficiently better than 45 ACP to justify another caliber. He explained the ballistic differences, and I was astounded. He said the 10mm is the best one-caliber option for anything I could encounter in the AZ back country, from black bear to cartel mule. It's accurate, flat shooting, and hits with authority.
I still himmed and hawed, since a new caliber would mean new reloading dies, potentially even using small pistol primers, etc. He explained that for a trail gun, you don't shoot enough volume to justify reloading.
So now I'm sold. Tomorrow morning I become a 10mm owner. It'll be a dedicated desert trail gun.
For my scenario, I've determined 10mm is entirely justifiable over 45 ACP for a dedicated back country carry piece.