Not likely, the S&W case is already loaded to the max and that is for a short barrel, in a handi barrel it will be good to get handgun velocities out of it. Once the powder has burned up in the first 10" of the rifle barrel, the rest of the travel down the bore is just drag on the bullet. The .45-70 or .50 Alaskan would be a much better choice in a rifle.
While the .45-70 is a fine cartridge, loaded to max velocities in a Handi is not what any normal shooter would do. As someone who has shot brown bear with a .45-70, and seen them shot with about everything, IMO the larger the bullet diameter the better
for a defensive use. This is the thread topic afterall, not which is the best hunting cartridge.
I'm not certain just where the idea that the .500 bullet will
slow down in a rifle barrel comes from, it is certainly not backed up by fact. Just because all the powder is burned up in the first 10" (if that is even true) hardly means that the bullet will slow down! As long as the gas velocity is higher than the bullet's, the bullet will continue to accelerate. Neither of us know what powder the factory loads in the .500, yet you assume it is a fast one. Okay....examples:
Sierra Edition V data for the .45 LC.
300-grain bullet, 15.8/15.9 grains of BlueDot
10" barrel = 1100 fps
16" barrel = 1450 fps
That's a nice 350 fps gain, or almost
600 fpe. Is BueDot too slow?
240-grain bullet, 11.5/11.6 grains of Unique
10" barrel = 1150 fps
16" barrel = 1350 fps
That's still a 200 fps gain, rather worthwhile IMO. We can expect the velocity to continue to increase as the barrel gets longer even with the low pressure .45LC; in the much higher-pressured .500 S&W the gas energy is higher still. Try the same data exercise with the higher pressured .44 Magnum and see. Eventually there would be a point of velocity drop, but that would be a very long tube not suited to the defensive role of this thread.
BTW I've fired a .50 Alaskan (years ago at Fuller's old Coopers Landing shop), and it was brutal in an 8.5 lb M1886 - I can only imagine what it would be in a light little Handi; there's not much metal left once the barrel is bored to .500" so the gun weight is pretty low. The .500 max-loaded with suitable cast bullets would provide all the recoil most defensive shooters would find tolerable along with ample stopping power. Flinching in a defensive situation could be fatal...
