Value is too difficult to be accurate without seeing the gun. Condition which includes the amount of original finish and original configuration will determine value. Recommend taking it to a gun shop for appraisal.
Browning Challenger made in 1974. $300-$400.
100-1000 USD depending on specifics.
For what? Accuracy, target shooting or beasts of the forest?
50-300 USd
350-400.
Type into a search engine on the internet.
Blue Book of Gun Values
It sounds like you need repairs done to a pistol. Recommend contacting the Browning Service Dept. at the link below. They will guide you as to the best way to get your gun repaired.
try: edssportshop.com
Mainly for target practice with aircraft mounted Browning .50 caliber machineguns.
Need to know iif its a revolver or semi-automatic and the caliber.
BLue book of gun values