Thanks for responding Matti and Gippeto (I'm not sure how to tag you here).

I think I can answer your questions by providing a few more details.

The company (startup) I work for produces a thin film for windshields and part of my job is to test its ability to stop windshield breakage from stone ...

I work in a materials testing lab that currently uses a calibrated slingshot for firing steel BBs. The slingshot frequently needs to be recalibrated since the elastic stiffens over time, and we'd like to overcome this issue by using a pressurized gas system.

We need to fire 3/8" steel bbs for our ...