Like different cars use different types of oil – synthetic, synthetic blend, conventional, 10W30, 0W20 and so-on, different types of paintball guns are lubricated with different types of oil or grease. Most paintball guns are delivered with an owner’s manual that will provide the manufacturer’s recommendations for how, when and where to lubricate, and with what. However, general rules are:
Blow-back paintball guns like the Valken Blackhawk, Tippmann 98 Custom, the Tippmann A5, the Spyder line, etc are lubricated with paintball gun oil like Valken Tango Premium Oil. This type of paintball-specific oil is designed for use with paintball guns and will work well with CO2 and compressed air on o-rings and to lubricate metal parts.
https://www.valken.com/products/lube-valken-tango-premium-lube-2oz
Spool valve paintball guns like the Eclipse EMek, GTek 170R, Eclipse Etha, GOG eNMEy, all the way through high-end paintball guns like the Eclipse CS2, Dye M3+ and Luxe X are lubricated with grease. Paintball-specific grease is applied to moving metal parts and seals to ensure proper lubrication, smooth function and to prevent wear.