For a simple BB or Pellet gun a cardboard box filled with newspapers old catalogues will do. But if you want to go high tech then you will need ballistic putty from Pyramydair on the web. In fact they sell a trap already complete. "Air Venturi Quiet Pellet Trap, Incl. Ballistic Putty + Steel Backstop."
A Earthbank would be your best bet man.
You need to state "MADE by Who" there are over 100 different companies that make pellet rifles.
The Crosman Recruit is a pellet rifle not a pellet gun. If you want to see how the rifle is assembled then see the link below for the diagram.
Only if the rifle is designed for pellets. If it is a "Red Ryder" then the answer is NO. Daisy makes PELLET rifles.
A 50 caliber Pellet gun (rifle) is a precharged pneumatic air rifle. It uses a scuba tank or compressor to charge the rifle. It can fire up to a 50 cal pellet. Companies like Shin Sung and others make air rifles this large. You can find the on the web. Places like "Pyrmyd air" sell them.
you dont
It's a 16 shot BB repeater or a SINGLE shot pellet rifle
Not normally. In fact I can not think of any pellet rifle that takes a 16 gram C02 cartridge.
For a backstop for your target, an earthen bank.
Impossible to answer.
The best for what? Paintball, .177 Pellet, 6 mm pellet or bb rifle?
In general, an air rifle will drive a pellet faster, since the longer barrel permits the pellet to be pushed for a longer time.