MAPP is a mixture of gases such as LPG (Liquified Petrolium Gas) and a type of acetylene (methylacetylene). Unlike acetylene if is stored as a liquid.
Like acetylene it needs a great deal of pure oxygen to burn efficiently. For this reason it needs special torches, often with a direct oxygen supply.
Simply screwing a MAPP gas cylinder onto a torch that was made for Propane usually results in a sooty low temperature flame that isn't good for much of anything.
If you have one of these Propane torches, stick to the Propane that they were designed for.
A few years ago I bought a Bernz-O-Matic torch outfit for around $40. It uses a MAPP cylinder and a red-orange painted tank of oxygen to feed the two hoses to the torch tip.
This oxygen tank is the same size as a regular small tank of Propane.
This outfit will produce temperatures in excess of 5,000 degrees F and can be used for brazing and welding thin steel sheet metal.
To light it, you turn on the MAPP and use a striker just like an acetylene rig.
Once the flame is lit you turn on the oxygen to get the flame needed for the task.
I cannot say very many good things about this rig.
The valves are very "touchy" and hard to adjust.
The oxygen cylinder is quite expensive and it doesn't last very long.
On the plus side, once adjusted it is hot enough to do a small welding job on very thin sheet metal.
I doubt that steel thicker than 1/8 inch could be welded with it though and any job that needs much welding will probably drain the oxygen tank before your finished.
For 95 percent of the work that needs to be done on a muzzleloader a simple, low cost Propane torch (or perhaps two of them aimed at the same point) is the most that anyone needs to solder or case harden small steel parts.
