I believe yesterday you worded this question very differentlyYou said "mothballed" so how long had the gun been left unused ?
seals can go hard & then fail, lube can both go hard or turn in to 'glue', or a moving part stick in use, it depends on many things.
It obviously needs looking at &/or a service, so if you can't DIY it needs to go to someone who can, be that a local dealer or back to the maker.