I've secured those airsofts just last month, use green gas or propane, the adaptors to use the propane tanks are essential to low cost refilling [ got 5 of them ] and now have 8 total including 5 KWA and 3 KSC g17's. One of them is a g18 full auto but I get to use that exclusively:rolf
SwampRat and I may eventually offer a class in Fla using my gas guns, supplying holsters, mags, pellets and gas [ all inclusive equipment rental ] if people are having trouble finding enough ammo for the ITFTS pistol course.
The idea is to shoot the airsofts to learn the skill, run 50 rds through the students real guns to have them gain the confidence in that skill and then move on to the airsofts with another skill, repeat and rinse throughout the weekend until Sunday after, then run some FoF training scenarios with the skills learned with the airsofts Sunday afternoon.
Precision airsoft is a good company to deal with. Not the cheapest but the best service later if you have a problem with the equipment, they'll stand behind it.