Do you mean Sears not sear. It would help if you stated the model number. Without that it is not very easy to answer your question, if it is a SEARS model. But I can give you this bit of information. It was either made by Daisy or Crosman air gun company. I suggest you do a search for "Air gun Repair" in Google and locate someone near you to repair your pellet gun.
No. a 177 is a 4.5mm pellet. A 5mm is a 20 cal pellet. A 5.5mm is a 22 cal pellet Don't try it in the wrong airgun.
Crosman still has some parts available for this model. See the link below.
It would help if you stated the model number. Crosman made several pellet rifles for Sears. You need to provide more information.
It all depends on the rifle, pellet and power source.
It was not designed for 25 cal ammunition.
When you say Air Rifle you are referring to a pellet rifle not a firearm. At present there are no 300 Cal air rifle being made.
this particular item is a .22 cal. pellet gun
show me breakdown &parts for J.C. Higgins 22 cal. rifle
u will need to ask a gunsmith for help
Yes it is possible. An air soft gun will not kill you but a pellet rifle is capable if killing a person. Pellet rifles come in several calibers. .177, .20, .22, .25, 9mm, 45 cal and 50 cal. The last 3 calibers are fired from a PCP pellet rifle. This rifle (PCP) uses a scuba tank to charge the rifle with 3000 psi of air. All of these pellets are capable of injury or death.
Crosman never made a .22 cal BB rifle. They made several .22 Cal Pellet rifles over the years. Several are still in production.
The Olympic air pistol and air rifle events use a .177 caliber pellet. The biathlon (skiing and shooting) uses a .22 caliber rim fire rifle.