I have 2 Crosman 99, lever action pellet rifles.
Once or twice I have had a pellet lodged in the barrel. I draw the distinction between "lodged" & "jammed", as in my case it is normally caused from low CO2 or pellet getting damaged in loading process.
I find that if I cock the lever & leave it open, the barrel will be open to the loading chamber, and then push the pellet out with a 3/16 x 48 wood dowel. A little bit tricky to do. You almost need 3 hands to do it properly, but this seems to work for me. But have never had one or multiple pellets jammed tightly in the barrel.
Of course, only do above steps once CO2 & all other pellets are removed.
Since it has 2 power setting, I try to shoot it on lower power, until power starts to drop off, and then only take a couple more shots at high power (by pulling the hammer back), before I replace the CO2. Just remember CO2 is cheap, sending it in for repairs can be expensive.
Regarding repairing the seals, etc. I have used R&R Airgun Repair in Stonewall, Manitoba, to repair both of them. He does good work & is reasonably priced.
http://www.randrairgunrepair.com/The Crosman 99 is a quality vintage air rifle. All metal & real wood parts. It is said to be a replica of the Savage 99 rifle (though I'm not convinced).
It can be a little bit picky about the pellets you use (flathead pellets seem to not load properly, so I switched to round head or hollow points). But has nice accuracy, and functions (cycles) well, once you get use to it. I try to only load 12-13 pellets in the internal magazine (vs. 15 as advertised) to avoid damage to the loading spring.
I have only used it for plinking & target shooting. Have not tried it for pest control, as it shoots at only around 450 fps on high power and around 395 on low. And as with most CO2 air rifles, the power drops off after using it and is temperature dependent.
Wish Crosman would consider re-introducing this air rifle. Is one of the few lever action, replica, .22 cal. CO2 air rifle around.
Good luck.