That wax bullet idea has me thinking. How much power do they have? Could the shotgun primer be used to propel some other type of bullet for small game use?

I mean, if that were the case, something like a .454 Casull or .460 S&W revolver would make for quite a versatile handgun.

Re-loadable shotgun primer powered loads for inexpensive practice and small game shooting. Standard .45 Long Colt loads for most duties. .454 Casull or .460 S&W loads for larger animal defense or hunting.

That's pretty good thinking!

However, be careful with low-powered loads and lead bullets though, lest you find one of them be-stuck in your barrel with another round traveling down the same barrel behind it. ;-)

I believe you'd find that any primer-only driven load might not have enough steam to push a real lead projectile of stable cross-sectional dimension for it's caliber out of the barrel.

I think I read somewhere that the wax bullets make about 600 fps and might pretty well knock the wind out of a little game animal if it hit them in the right spot. In my Vaquero, though, the wax bullets shoot a few inches lower than my actual point of aim at about 17 feet. They'll hit in about a 1 inch circle with a half-way decent attempt at aiming at that distance.

A shot shell might be easier and more effective.