Older Benjamin pellet rifle loses power after sitting cocked?


PDA






Macchina
June 15, 2014, 10:27 PM
My brother inherited my Dad's .22 Benjamin, it's a 1980s-1990s vintage break-barrel rifle that has been used in the past four significant small game/pest hunting.

My father followed all the lubricating advice the gun shop gave him, my brother has not for the past 3 years (I believe).

My brother reports that the gun shots almost as strong as it used to when freshly cocked, however if it's cocked for an hour or more it "will bounce off a chipmunk or a tree".

Is this a common problem? Any suggestions?

If you enjoyed reading about "Older Benjamin pellet rifle loses power after sitting cocked?" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
Chevota
June 15, 2014, 11:50 PM
I have a theory, but I can't imagine it being true. Then again anything is possible with a chinese made gun. If the bore of the receiver tube was larger at the breech end/smaller in the middle, then when cocked the seal would take the smaller shape with time and leak when it went down the larger bore. The less time it had to take the smaller shape the less it would leak. Make sense? I know most if not all of the Crosman/Benj guns I've worked on were smaller in diameter at the very back, but the section the seal rides in has been consistent. So I'd say lube the chamber/main seal since I probably needs it anyway and it might even make a difference, but if it were me I'd open it up and replace the main seal, maybe even the spring, and look-c for anything weird.

rcmodel
June 16, 2014, 12:46 AM
Thats a possibility I suppose.

But there is no physical reason the spring would lose power when left cocked, then regain it back after firing and re-cocking it again.

Firing it heats whatever oil is still on the piston seal, and makes it soft enough to work till it cools off again.

I would say the seals are dry, and it needs to be re-oiled with air gun oil again sometime soon!

Use Real Air Gun oil, not just any machine oil you find in the shop.

rc

Macchina
June 16, 2014, 09:07 AM
I thought something may be going on like RC is talking about... I'll definitely oil it first.

If you enjoyed reading about "Older Benjamin pellet rifle loses power after sitting cocked?" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!