No problem with the "run of the mill" factory ammo in your Contender. I handload for my 8" 45-70 because the barrel is so short that a lot of the powder burns off in the air (a HUGE fireball!). Recoil is stiff, so be ready! I use a soft leather glove on my shooting hand for repeated shots. After a couple of shots, the trigger guard starts beating on my fingers, so the glove helps with that.
Oh yea, don't be trying to hold your Contender by the forearm with your non-shooting hand! Hold onto that sucker like you would any other pistol, just keep your index finger out from behind the trigger guard or it will get bit! Look around YouTube for those knuckleheads shooting that 700 Nitro Encore pistol to see what can happen if you don't have a good grip on it!
I have shot real Black Powder in my 8 incher, it's a hoot!