Anyone have any pics and info concerning the "automotive style" piston rings in the FWB300 match rifle? I know that with an automotive piston you have multiple piston rings with gaps between the ends, an oil control ring, and you do get blow by around /through the ring joint gaps.

I'm wondering how FWB accomplishes the "miracle" of using steel piston rings without getting any blow-by, or do they indeed get blow-by but it's insignificant due to the low power output?

much like a small two cycle engine. it is a split ring but when in the gun the gap is very small. That small gap has a hard time blowing by any air because it is compressed so fast. I had a 300.

These are low powered guns. not sure how a system like this would work in a gun like a tx or R9 like you have. I think it takes a very precisely honed tube for a steel ring to work and it just am y not be suited to high power.

but the tolerances of the ring to the comp tube are super tight, probably less than .005". Also,the system requires a bumper on the end of the piston, which doesn't seal but cushions the piston as it slams into the end of the tube. I'll look for pics when I get a chance.

The FWB300S is a model of German over-engineering. If that gun was made today it would probably cost at least $3K... so many precision parts expertly fitted by craftsmen of the day. The piston cylinder in the 300S is hardened and ground to precise tolerances IMO closer than a typical automobile engine as there isn't a wide temperature operating cycle. The piston ring gap is very small, maybe a couple thousandths and oil easily keeps a seal inside the super smooth cylinder chamber. The low velocity powerplant unlike other spring-piston power plants looses more oil due to evaporation than it burns.

Airguns are a gas

Boomer

Here are pics from when mine was apart for a rebuild. Shows the old one and the new one. Also shows the piston with the old one in place and a shot with the ring removed from the piston....














Arnold
The one who is good at shooting does not hit the center of the target.

Does the end of the comp. tube come out of the 77? It would be pretty easy to get a perfect comp. tube bore if it does. I know the TX tube is super hard and any competent machinist can hone one to perfection. The piston ring would be another story, but if you could find one to fit your application, looks like you could file the end gap to perfection as well.

Does the end of the comp. tube come out of the 77? It would be pretty easy to get a perfect comp. tube bore if it does. I know the TX tube is super hard and any competent machinist can hone one to perfection. The piston ring would be another story, but if you could find one to fit your application, looks like you could file the end gap to perfection as well.