Does anyone know what kind of fps i could expect out of a 1720t by just changing to a .080 TP and using the stroke adjustment and hammer spring adjustment? I would like to get up around 800 fps 12fpe with JSB 8.4gr pellets . Or will i have to go with a bigger TP ?
I have the same setup in my 1720T.
I have added a 4 o-ring BHB and a bit stronger hammer spring.
Here are the numbers with 7.33 JSB:
Nice string!
You may be able to get it up to 12fpe but it won't be very efficient. A generous transfer port and a short valve dwell will make better use of air.
I drilled out a transfer port to 0.094" and used a bstaley O-ring buffer to tune a 1720T for my friend. Ended up with a very nice 34-shot string inside of a 4% ES, peaking right at 12fpe (11.4fpe average).
https://www.gatewaytoairguns.org/GTA/index.php?topic=86564.msg832336#msg832336
Thanks for the information i have book marked it for future use.