OK. my daugter has a b1-1 break barrel, She has shot around 400 pellets through, I tore that thing down to have a look at the inards. here is what I found
The leather breech seal is doing it's job, Barrel lock up is good and snug, no play.
On the inside, compression chamber is actualy pretty smooth, the piston is realy rough, plenty of burrs and bad machining marks, the leather piston seal is hard as a rock and tight in the chamber still plenty of china lube in there, and the leather seal is deformed and starting to tear seperate, the ends of the spring are not even and are very sharp, the trigger sear engagement on the piston rod looks ok, and the trigger looks ok also, the trigger although a little hard was fairly smooth on this one. When cocked the spring is near coil bind, just guessing while I took it apart about 2 + inches of pre load on the spring, and as noted before the spring is almost coil bound when cocked. The transfer port is drilled of center, and does not align quite right with the barrel bore, close but not quite.
I'm curios if the b1-1 and the b2-2 use the same spring, and have the same compression stroke?
I'll polish this b1-1 up a little and reassemble, with a new seal. and see what happens.