First off let�s make sure what I know is true:

I know rifle primers are harder than pistol primers (in general).
Rifle primers have more power (flash, bang, pop) than pistol primers.
I know that magnum primers have more power (flash, bang, pop) than regular primers.
I know that if I use pistol primers in a rifle I may end up with a pierced primer, or a load not going off.

Assume the above is true; why not use rifle primers in my pistol loads?
If I did this, I assume I need to reduce my pistol loads, right?

Other than reducing the load, the only complication MIGHT be a failure to ignite.
Handguns with hammers will probably ignite fine, those that don't use hammers however might give you problems.

Because rifle primer pockets are deepr than pistol primer pockets.

Why not use heating oil in your gasoline engine? They both burn...