It would help if you stated the model. So here is what I can do. Crosman owns Benjamin air guns, they offer a service to locate repair shops that repair older Benjamin products. See the link below.
go on the computer and scan the words 'marksman air pistol' ...............
To repair a SAM M10 air pistol, first ensure that you have the right tools, including screwdrivers and lubricants. Disassemble the pistol carefully, noting the arrangement of parts, and inspect for any damaged components like seals or springs. Replace any faulty parts, clean the internal mechanisms, and apply appropriate lubricant. Finally, reassemble the pistol, ensuring all parts are securely in place before testing its functionality.
It will shoot pellets or bb's. They normally use an air cartridge.
The most powerful air pistol would be a Air Force Talon-p 25 Caliber. This is a PCP class air pistol. The air tank uses 3000 PSI to fire the pistol.
A regular pistol is a firearm. It uses gunpowder to fire a bullet. An air pistol uses compressed air to fire a pellet with less velocity than a firearm.
you can start by searching the web for "Airgun Repair' or see the link below.
See the related link at the bottom of this page to see the Crosman 1088 parts manual.
This pistol was made between 1978 and 1984. Crosman no longer supplies parts for this model, But the offer a free service to locate shops that repair older Crosman air guns. See the link below
For the parts list and the owners manual see the two links I've posted below
This is a .22 caliber air pistol not a .177 caliber pistol. See the link below for the owners manual.
You might be able to get it from Daisy. See the attached link below. request the parts list
Contact Daisy directly (Customer Service) and select the parts manual. See the link below.