Crosman 454 bb pistol

The Crosman 454 is CO2 powered, semi-auto BB gun that was styled after the Colt Woodsman. It has a sixteen shot magazine, and adjustable rear sights. These guns were manufactured between 1972 and 1977

I recently went through this pistol and replaced the seals, and lubed it. It had a bb feed issues. I polished the bb receiver. Sanded the plastic bb pusher. It still did the same thing. I noticed the bb's were snagging in the valve block, catching on the lip of the barrel. Backed out the barrel. .5 millimeters. Checked everything they now feed through. Put the gun back together. , It was crony after seals, first five shots at 387fps. next five averaged 364 fps. Now its shooting like new. I will be shooting it at paper from 25 feet off hand.