I'll try these, and I've broken them up for us!
Not being a 10MM or 40cal owner, whats so special about them?
This is gonna be a two part answer because it's hard to tell if you are asking what's special about a 10mm or what's special about a S&W 10xx or more specifically, what's special about a 1086?
--the 10mm cartridge is kind of niche but when you consider
MOST of us on this forum are hardcore hobbyist types, we love our niche stuff! I know one poster in particular that has a rabid fondness for nickel plated S&W Model 39's and those have been out of production for 40+ years!
But yes, the 10mm will ballistically out perform a .40cal and a 9mm, and in a S&W 3rd Gen, it comes at the cost of size, weight and capacity. But the cartridge can bring a lot of bullet weight at what is going to be argued "magnum revolver" bullet speed, and this makes for a pretty potent handgun package
--the S&W 10xx pistols were (arguably!) the first pistols on the market that were actually built for the full range of the energetic 10mm cartridge. The Colt Delta Elite had frame cracking issues and poor case head support and heavy loads just bork up cartridge brass. The infamous D&D Bren Ten had more issues than I have keystrokes for. The 10xx guns that S&W built were hell for stout and with no asterisks. S&W took full-size .45 Auto pistols, with .45cal sized barrels and cut a smaller .40cal sized hole, leaving
more metal and more meat around the chamber and bore for the 10mm cartridge. For anyone paying attention, this is 180 degrees the opposite of the S&W .40cal pistols... and almost every other gunmaker's .40cal pistols. Most .40cal pistols are 9mm frames and 9mm slides and breech faces, 9mm barrels and chambers and all opened up to .40cal, using up that metal and leaving you with less structure at every angle. And the S&W 10xx pistols is the complete and total opposite.
These guns are big, strong, and awesome.
--to the 1086 specifically, only 1,660 were (allegedly) manufactured over the short four year run of the 10xx series, itself limited to just under 51,000 total made. So yes, the 1086 is a special one that is hard to find.
Do they out perform a 9MM or 45ACP?
They absolutely do specifically out-perform both cartridges, but this of course depends on your GOALS. Does a 10mm do a better job at taking out a meth-addled lunatic? I have no idea, but .308 is a better choice for that. Now if you want to have some wild boar hunting or bear defense, then yes, the 10mm out-performs 9mm and .45. And again, it comes at the cost of capacity (to the 9mm) and recoil and muzzle flip (to the .45) and the cost and availability of ammo to both.
I don't, but I would probably love the interior temperature! And I do make most of my ammo in one.
