Crosman never made a model 1881, but they did make a model 1861 called the Shiloh. If this is the gun you are asking about then see the link below
Crosman Corp still has the Owners Manual online. You can find your manual here. see the link below
Unfortunately the parts manual is no longer available from Crosman but the owners manual is. See the related link.
See the Crosman link below and select your rifle for the diagram and owners manual.
If you have the original C02 bottle. Crosman warns you NOT to use it. see the link below for the owners manual from Crosman.
This model was made for Sears by Crosman. It is a Crosman model 160. For the owners manual see the link below.
Crosman Corp still has the Owners Manual online. See the link below)
Crosman still has parts available for this model. See the links below for the parts manual and Crosman customer service.
Most makers have manuals on line or will supply one for free if you contact them. -----------------------New answer----------------------------------- See the link below for the Crosman model 160 Owners manual.
I have extensive resource books on airguns. But can not find anything about the model 1800. I do know that it exist. It was the model 1800 powermatic. I think it is similar to a model 1600 powermatic but I do not know the difference. I suggest you contact Crosman Customer service and ask for an owners manual see the link below for the 1600 owners manual and Crosman customer service web page.
The Crosman 400 is rated at 450 FPS. See the link below for the owners manual
this rifle was made by Crosman for Sears under the JC Higgins brand name. It's really a Crosman model 166. Originally it was the HAHN repeater but Crosman bought out Hahn and continued the model as a model 166 for Crosman 1958-1971. See the link below for the Owners Manual.
Crosman still has parts available for this model. You can order directly from them. I've attached a link below of all the Owners and parts manual for Crosman rifles. (it's a Crosman web page) Find your model and open the parts diagram Then call Crosman customer service and order your needed parts. Crosman is spelled with One "S"