RE: Why did you buy "that" caliber?
I bought my Ruger No. 1's, because I always liked single-shots. Same with the TCR, plus it was supposed to have a lot of different caliber barrels available. Of course, then T/C stopped making the TCR barrels....But the No. 1's don't have interchangeable barrels, so I had to buy a lot of them to get the calibers that interested me, from .25/'06 up to .416 Rigby.
I built a couple of rifles on bolt actions because I wanted to experiment with the odd calibersa, like 6mm/284....
Of course, muzzleloaders speak for themselves, but I had to build a couple of these too, to get a fullstock Hawken .58 flintlock and a flintlock Jaeger in .73 cal. The M1 was needed to use in HP rifle competition. Likewise the Colt Gold Cups in .38 Spec and .45 ACP, and the Browning Medalist .22. (Bullseye pistol). The S&W M29 and Taurus ,454 Casull, and Ruger Old Army are strictly hunting weapons.
Then there are the fun guns, like the Dan'l Fraser .22 Hornet, the .30 M1 carbine, and the Ruger No. 3 .30/40 Krag, plus the Ven. M1924 FN Mauser in 7X57mm,the M1909 Argentine 7.65X563mm, and the best of all, the Mannlicher/SchoenauerMCA carbine in 7X57mm...... oops! Forgot the HEYM M55/77 combo, 3" 20 GA over .30/06 w/ a set of 12X12barrels, and the J.P. Sauer 8X60RS double rifle.....
Why did I buy them all? Well, it seemed like a good idea at the time.
I have very few guns left. I sat down and started listing all the guns I've owned over the years, starting with the nice Jap Nambu 8mm pistol my uncle brought me from WWII when he came back. The total that I could remember came to 177..Most have been sold or traded, some just given to friends over the years. But I got to shoot, and to load ammo for, most of them!