If you want to determine wich caliber is better for you, start by knowing the purpose of the gun. It can be target shooting, self defence and the such.
if you want to determine the caliber because who came across a gun for any reason such as passed down to you trough generation or inheritance, then you have to check the model and make wich should be stamped in the firearm itself and any gunsmith can tell you the caliber if the weapon does not state it wich it will be a rare case. Very old weapons did not have the caliber imprinted. Now a days I can not think of a firearm that does not have the caliber of its ammunition imprinted on it.
Blue Book of Gun Values
Yes
Cal .177
It all depends on the model. Please state the model to get an answer.
Who is the manufacture of this BB gun.
No such weapon
this particular item is a .22 cal. pellet gun
The value of a Marlin Cal bolt action model 187 gun depends on its condition. This gun in excellent condition is worth between 90.00 and 135.00 as of 2014.
Lets see there are over 1000 different model .177 cal BB guns in the world today. It would help if you stated the model number in your question.
Try gun shop, gun show, pawn shop, egunparts
Try gun shop, gun show, want ads
Gun shop, gun show, on-line firearms auction.