Message-ID: 
Newsgroups: AIRGUN.LIST
I have not had a lot to do with pump rifles ( maybe we are too idle here in
UK to use them) but as they use compressed air which alters with
temperature could it be that fast pumps generate heat during the pump cycle
and the air cools leaving less pressure in the reserviour with a consequent
drop in velocity. Conversly slow pumps give cooler air  with no pressure
drop - just a thought
Keith Mepham
--- QScan/PCB v1.19b / 01-0671
---------------