My 40 Smith & Wesson loads run about 100 ft./s faster for the same bullet weight as most factory 10 mm loads. And said loads are a couple of grains below max per reloading manual. Why bother with a 10 mm for practice? I've always thought it ironic that many refer to Smith and Wesson 40 as short and week. The truth is it is a very powerful round when loaded to the high-end of the scale.
I'm not sure I understand your post clearly.
I agree, most factory 10mm ammo is pretty poor when considering the potency of upper level 10mm loadings, and I agree that 40 S&W is a fine cartridge. It does the job well. Calling it short and week is silly. It may be short, but week is not accurate. Chest thumpers are loud though.
If a person only wants to shoot loads equivalent to a 40 S&W, a 10mm is kind of an unnecessary investment, and will require a 45 acp sized frame. But it's kind of like someone who wants a 357 but really only intends to shoot 38 special, or 44 mag/44spl. They like the option of magnum velocity, even if they rarely use it. I also suspect some folks don't care for the recoil of full power loads, but realize it after they get a 10mm. Rental ranges are not everywhere, and even when they are, they may not have a 10mm, or the 10mm the shooter wants to try. A poor fitting gun/shooter combo can give a very poor impression of 10mm or really any cartridge if the gun doesn't suite the shooter.
Some just want fun soft shooting loads and enjoy having a gun that is more than capable of outlasting the shooter's life span due to being overbuilt for their purposes.
I think you are looking at it as "If you want to shoot 40 S&W, just get a 40 S&W." While some folks see it as "I want to be able to shoot 10mm full power stuff, and I want to be able to shoot something equivalent to 40 S&W loads, so I'll get the 10mm and buy a variety of different power ammo." IS this an accurate assessment of your assertion?
I think the nice part about buying factory ammo that is watered down, is that as this thread points out, you can get it relatively cheaply, at least cheaper than full power ammo. It makes sense. Cheaper bullets and less powder should result in cheaper ammo. If you are a reloader, then you get the brass as well. I prefer to just buy Starline Brass, bullets, primers, and some AA#9, and load my own to mid range 10mm levels. (1250 fps range)
Like the 9 mm the case is full of powder and very efficient. Unlike the 45 ACP and 10 mm which are roomier cases. Although large bullet do fill 10 mm case nicely.
I agree on the benefit of being able to load longer and heavier bullets in the 10mm. It's clearly a benefit. I'm not sure though that I agree with the assertion that 45 and 10mm are less efficient cases. 45 can be loaded pretty warm given the right powder, and there isn't a ton of room left in the case with some powders. I mean it isn't typically anywhere near compressed, but it's not like ignition is ever a problem due to powder position. My 10mm loads have powder right up to the base of the bullet.
