I have absolutely no information on a Crosman model 143. Are you sure it isn't a model 140 or model 147. I even searched the net and can not find anything on a model 143.
Go to ( See the link below ) and find your parts and owners manual for your gun or rifle. Crosman keeps a web page for older airguns.
You follow the link below to the Crosman website Customer Service section, download the manual for the 140, and read it.
This is a two part answer for you. First the Rifle was made by Crosman air guns. Any JC Higgins air gun starting with 126 was made by Crosman any model starting with 799 was made by Daisy air gun. My Catalog list the 126-1930 as a Crosman 140/1400 the 1400 was a later model of the 140. This makes me think that the 1930(1) represents the 1400 model (Check Youtube and look for a Crosman 1400 and see if this is your model). If So then the rifle is worth around. $75 plus or minus. The 1400 rifle was made between 1968-78. Its a pump rifle that shoots a .22 cal pellet at 580 feet per second.
This is a model 1400 or 140 made by Crosman and would be worth around $80-$95 depending on the working condition of the rifle. Depending on the variation, It was made between 1954-68.
1954 to 1968
It would be worth around $80 to $100.
This model was made for Sears using the JC Higgins brand name. It was made by Crosman and is really a Crosman model 140 or 1400. Crosman offers a service to locate repair centers that repair older Crosman air guns. See the links below.
The Crosman 140 Air Rifle was made from 1954 to 1968 in four different variations. Crosman no longer makes parts for the rifle but you can still get it repaired. The Crosman home page offers a "Find a repair center" button on their first page. From there you can locate a center that has parts for your rifle. See the related link.
THIS IS A CROSMAN. It is a Crosman model 140 or 1400
Crosman no longer has parts for this rifle. However there are independent shops that repair older Crosman air guns. Crosman offers a free service to locate these shops. see the link below.
The rifle will fire without a pellet, but over time it will ruin the air chamber and air piston inside the chamber. When you pull the trigger the air piston slides forward inside the air chamber compressing the air behind the pellet. At the last moment it actually slows down as the pressure builds and fires the pellet. Without a pellet in the loading port the piston has no resistance and just slams against the stop. This will eventually ruin the rifle.