well you get the instuctions out and wallah you guns assembled
It depends on what type of gun it is. You should check the owners manual.
a .45 caliber.
No! What's the matter with you?
45 caliber Machine Gun and 50 caliber machine gun
a .45 caliber.
The short answer is no. The longer answer is, you might be able to get a .40 caliber cartridge to fire from a .45 caliber gun, but it may damage the gun, and even if it doesn't damage the gun, it will cause other problems. In general (with only a few exceptions) you should never try to fire any cartridge in any gun other than a gun designed for that caliber.
Anywhere from $50 to $25,000. Depends on which gun. Caliber 45 refers to the size of the bullet, and nothing else.
yes
No.
45 colt
.45 ACP
If you are talking about a PCP (PreCharged Pneumatic) rifle. With a .45 caliber pellet, then "Yes" It can. I don't believe there is a 40 Caliber pellet gun.