A friend of mine has a Benjamin hand-pump air rifle he had overhauled about a year ago. It has just sat, since.

He tried to shoot it today. He can pump up pressure just fine, and the gun holds it. When he pulls the trigger, he says it feels "spongy" and the gun won't shoot. Apparently it won't release the pressure.
Any idears?

If it's like my Sheridan when you pull the trigger a plunger strikes the air valve which releases the compressed air. Take the action out of the stock and see if the plunger moves rearward when you pull the bolt back to cock it. The plunger should be under spring tension which is what you feel when pull the bolt back.

We'll try that. Stay tuned!

If the release valve in the air cyl. isn't seating completely, the pumping will feel normal, but the pressure will escape thru the barrel w/each pump. Then when you cock it and pull the trigger, the striker will just kind of "boing" against the release valve. Be sure you use only a light mineral oil (e.g. Crosman Pellgunoil) to lubricate it. Petroleum oils will attack the O-rings.
I'll be watching this thread - please keep us posted.

Larry

Thanks, Larry.
We're a couple hours later than you so this'll be a mañana project. I will post results.

I own several Benjamin air rifles and pistols. I even have my 1st Benjamin from Christmas of 76. It has been rebuilt once. I have always used 3-In-One oil, without ANY problems, to lube the plunger assembly area.