It's hard to advise you on how to field strip your crosman air gun when you don't identify which one you are asking about. So I suggest that you go to (see the link below) and at the bottom of the page you click on "Download a Manual" and locate you airgun. It will give you an exploded view of the parts.
They are both the same size. .177
The Crosman model 761XL is designed to shoot BB's or any .177 Caliber pellet. These are the most common pellets you can find. Make sure you select .177 Caliber pellets.
The Crosman 760 doesn't shoot Bullets it shoots BB's or .177 caliber Pellets.
No it is not possible (in the USA) Crosman only makes the Phantom in a 177 Caliber. However I believe the Phantom .22 is made for Canada and Yes it will kill a bird.
It would be worth between $65 - $75
Any .177 caliber BB is fine. BB's made by Copperhead or Daisy will work with your 760.
The C-11 shoots .177 Caliber BB's not pellets
It would be worth around $65 in Excellent shape.
New in box $90 add 20% for original Box. Mfg 1964 to 1985 it came in .177 caliber and .22 caliber
The model 100 is a .177 caliber air rifle. The model 101 is a .22 Caliber rifle. Basically the same air rifle just different calibers.
The Crosman 1300 Medalist II was made between 1970-1976 as a .177 caliber and the model 1322 medalist was made from 1977-2000 as a .22 caliber. It is no longer in production. One in perfect condition will cost you around $80 plus if you can find one.
It is designed to shoot .177 Caliber pellets, not BB's. It has a rifled barrel, BB's will ruin the barrel if they are forced to shoot through it.