Just picked up today the following:

Humphrey 25-SP-1 air cylinder

See page 150 in this link

http://www.controlandpower.com/catalog/PDFs/Humphrey/Humphrey%20Actuators%20-%20SS.pdfhttp://www.controlandpower.com/catal...tuators%20-%20 SS.pdf

and one of these

http://www.metalwork.it/eng/img/prodotti/cilindri/11GB04%20SSC.pdfhttp://www.metalwork.it/eng/img/prod...GB04%20SSC.pdf

This one is the double acting 63mm bore, 75mm stroke version

Before I stick theseon a bench and start building the pneumatic circuit I thought it would be worthwhile checking they are suitable for CO2.

The one which concerns me is the Humphrey one which is marketed as an air ram. Obviously there is a significant temperature difference between compressed air and CO2 so I thought Id check the significance of this.

Once Ive got some advice on this, Ill probably ask a few more questions on competition rules compliance, sizing etc.

Andy