I've always had a Sheridan 5mm or Benjamin .22 way back since junior high.
About 10 years ago I got into PCPs and had a couple Air Force rifles.
Lately I've wanted something for backyard plinking and didn't want to spend the better part of $1000 to do it.
I read about the QB rifles that guys have been tinkering with for at least a decade.
Wood and steel, traditional looks and feel, a Chinese copy of older Crosman Co2 designs. The QB-78 is a bit different in that it has a tube concealed in the fore end that holds two 12 gram Co2 cartridges. Guys have converted them to HPA by fitting longer tubes.
The QB-78 is better looking than the stubby fore end QB-79, but the 79 has a lot of fill options.
I can use a 12 gram cartridge with a metal tube adapter, and can also screw in a big 88 gram Co2 cartridge.
And best of all, use a high pressure air bottle that is 13 cu in./3000 psi.
The Tippman bottle is regulated to 850 psi, so I can get a lot of shots out of one fill.
First thing I do with these rifles, Chinese or otherwise, is scrub the factory preservative junk out, it takes a good 1/2 hour of alternating between patch and brush before they come out clean.
The stocks on the QBs are very comfortable and the trigger is 3 way adjustable.
I added a Hawke 3-9x AO Vantage in Sportsmatch rings. (Sportsmatch rings are made in Britain, very reasonably priced and well made and are a good alternative to all the cheap Chinese rings and mounts).
The QB-79 sells for $140 on Amazon.
Some guys run the 1100 psi Ninja tank on their QB. They're getting the .22 pellets up to 800 fps.
I considered doing that too, but I now have a new PCP that can get 900 plus, so I'm not too worried about hot-rodding the QB.
I like getting a couple hundred shots out of the big tank.
5 shot groups fired at 35 feet: