If you want to use a .40 LA I sugest you get a trainer that is lighter. The Nexstar is a 6.5 lb trainer. If you get an Tower Trainer it weighs about 5 lbs and that 1.5 lbs will make a world of difference.

http://www2.towerhobbies.com/cgi-bin...?&I=LXCAS2&P=0