RE: Remington 700 Muzzleloader
In addition to what Sabotloader said, you will definitelly need to protect your scope from ignition flash. My example was an early blued .50 caliber but was a very accurate rifle with a load of 90 grains of Pyro P and 400 grain PR Bullet Ultimate 1 conicals. The bolt cleaning can be a pain as it isn't exactly a quickly disassembled bolt.
You might check Kittery Trading Post's used guns section for price comparison on used rifles.