Colt makes a 1911-A1 Pellet gun made by Umarex. I know of no BB gun unless you are asking about an Air Soft gun. The Pellet gun is very good. I can not answer about an Air soft gun.
If this is an Airsoft gun then 6MM BB's should fit.
The Colt 25 airsoft BB gun cost between $10 - $15 depending on the model.
About 100yd
Colt makes several different models. Which one are you asking about?
It's probably an abbreviation for meters per second, the velocity of the BB.
Colt has 5 different model Air guns. The Defender is the only BB gun, the rest are pellet guns. Umarex makes all the airguns for colt. I suggest you contact UmarexUSA and ask them for assistance or repairs
You don't. It strictly a BB gun. It is not designed for Pellets.
See the link below for the owners manual.
I suggest the you contact an air gun repair shop to have it fixed. Try looking up "Air gun repair" on the web and have them repair it for you.
It looks like an old Colt 45. See the link below.
fps means feet per second the fps (feet per second) is usually more than 120 edit: The "feet per second" refers to the muzzle velocity of the gun, or the speed of an airsoft BB exiting the barrel. Since the muzzle velocity is different depending on the weight of the BB, make sure to check what weight of BB the muzzle velocity was measured with. Often, airsoft sellers will measure the muzzle velocity with a lighter BB to make the airsoft gun sound more powerful, so you may want to ask what the muzzle velocity is for the weight of BB you are going to use. Many airsoft parks will not allow airsoft guns (other than sniper rifles) to have a muzzle velocity significantly over 400 feet per second, so it is important to know if the gun is too powerful to use. Also, anything with a muzzle velocity under 175 fps will not launch BB's very far.