Check the Muzzleloading Reference for links and information on the products I will cover here.
The obvious starting point is the stuff that has been used for hundreds of years. Although it is tightly regulated both in shipping and storage you can get your hands on real black powder from several manufactures. It is classified as an explosive and must be handled with care. Swabbing between shots is a must as true black powder can be highly corrosive and unburned carbon is a large source of heavy fouling.
Pyrodex is probably the most readily available black powder substitute on the market. It is related by some ingredients to traditional black powder and shares many of the same pros and cons with black powder. However it is more stable and has a higher ignition temperature. It is just as corrosive as traditional black powder and swabbing between shots is a must. Pyrodex is equivalent by volume to black powder so 80gr by volume of pyrodex is roughly equivalent to 80gr black powder.
Pyrodex also comes in pellet forms over various sizes and volume equivalents. Pellets are preformed charges that allow for fast reloading and less hassle. You can only choose from several sizes so they give less flexibility in working up a load. However many people love the no hassle approach. To use pellets in a side lock muzzleloader it must be specifically designed with a special breech plug to properly ignite the pellets.
Triple Seven is a sugar based propellant much like model rocket engines. It is less corrosive than pyrodex and offers high velocities with less powder used. It is very popular with hunters and match shooters alike but is harder to ignite requiring 209 primers. Unless you have a 209 conversion kit you are out of luck with muzzleloader or #11 caps. Triple Seven does have one set back, it is known to leave a ring of fouling that can seize up breech plugs and make rounds hard to seat, swabbing between rounds is a must. Also unseating and re-seating the breech plug can keep it form being "frozen" by the crud ring. It is also harder to clean. Despite all this it is very popular with hunters and match shooters alike. You can purchase Triple Seven as a loose powder or in pellet form. Remeber if using loose powder follow loading data closely as Triple Seven does produce higher velocities.
Note: Blackpowder, Pyrodex and Triple Seven are sensitive to moisture and heat and must be stored in a dry cool place preferably in a tightly sealed container. Also leaving a charge loaded is never a good idea due to this as well as general safety issues. Claims are often made that Pyrodex has a "short shelf life", I contacted Hodgdon regarding this and was informed in part:
"There are only two conditions which lead to this product becoming unserviceable: 1) Moisture, just like black powder. Both of these products are made with components which can absorb moisture if they come in contact with it, just like black powder. Keeping the lid tightly screwed down on the container will solve this problem in storage. 2) Heat: if you raise the ambient temperature of these products to their ignition temperatures, they will destabilize and combust but not like black powder. Black powder is an explosive and will explode if it reaches its ignition temperature. Pyrodex and Triple Seven will deflagrate, not explode."
" What we do know is that they are unlike smokeless powder in this regard. All smokeless powders will eventually go bad and change dramatically. This is due to the way they are made in a reacted chemical process and acid reduction. There is no such worry with black powder, Pyrodex or Triple Seven."IMR White Hots:
Released recently ( 2009 ) IMR is owned by Hodgdon, the makers of Pyrodex and Triple Seven. IMR is only sold in pellet form and to the best of my knowledge is identical to Triple Seven. I have not done any testing with this product but have seen some people claim good results on targets and while hunting.
Black Horn 209:
Black Horn 209 is best performing powder currently on the market. It is less corrosive and leaves less fouling than any of the black powder substitutes on the market. You do not have to swab between shots and it is not affected by moisture as all the other powders are. It is however more expensive and harder to find. It is only sold in the loose powder form. It does require a 209 primer and is made to be used in modern, in-line muzzleloaders. As with triple seven follow the loading data closely as BH209 does create higher velocities with less powder.
There are a few other black powder substitute products on the market. Most are harder to find and/or not widely available.So I have not had a chance to test them out or talk to anyone that has tested them.
Primers are fairly straight forward there are three basic types musket cap, #11 cap and 209 shot gun. Most modern in-lines have breech plugs fitted for 209 primers. Some cap makers have magnum versions that are a marketed to be a bit more powerful to light some of the powders that have higher ignition temperatures. In 209's there are standard shotgun primers and special muzzleloader primers that are supposed to be cleaner burning. Follow the firearm and powder manufacturers recommendations as to what primers to use. Some powders will specifically specify standard shotgun primers as they are more powerful.