On another thread Alliance Hobby seems to be unresponsive for several months now. Best call before sending money.Too bad, I have done a lot of business with them in the past.
I assumed the OP was wanting to mount an 88 gr. on his gun ("hang it under the barrel"), not tether it with a hose.... Me bad!.... Of course you can hook it up to a remote CO2 tank, as large as you want (even a 20 lb. tank).... and shoot all year!....Bob