How would a Marauder perform on CO2? About like the Discovery or more velocity? I wouldn't mind having one sometime or the other, but I will be having back surgery soon, so I think hand pumps will be OUT for a good while, and the nearest scuba shop is 65 miles away from where I live. I plan on getting a Hammerli 850 .177 here in a few days, but the Marauder could be a thing for next year or so, depends upon recovery and finances I guess. Interesting rifle anyways! Thanks for any information friends.

since no one else is picking up. I have a .20cal Disco. with a stock valve, lightened hammer, and 18" barrel that shoots well over 700+ fps @72deg. on co2 without increasing the tension on the std hammer spring. Also have a .22 cal QB78, basically the same build, 18"barrel, standard volume valve, teflon stem, lightened hammer, stock spring tension, bulk fed long lower tube, shoots 750fps @ 72deg.
If the long barrel's work better for co2 adage is true, I'd imagine with a little tuning, you ought to be able to do better than me.
Anthony

Looks like not much interest shooting the Marauder with CO2. I'll search around some more to see what I can find. It looks interesting; if it shot say 12-15 foot pounds power, it would make a fine short range repeating hunting rifle. Good looking wood stock, shrouded barrel, adjustable trigger, accurate, repeater, and could be simply refilled from a cheapo paintball CO2 bottle. I have a bad lower back problem and will probably be having surgery soon to correct it, so the option of shooting with CO2 instead of using HPA pumps is interesting to me.

I used co2 in my disco but have not yet in the Marauder. For me it's much cheaper to use hpa from a scuba fill (4 dollars) then to use co2 (7.50 for a 20oz). And I get more shots from the scuba. It's probably quieter (!) and lower velocity around 650-700. The disco gets @60 good shots.

Looks like the Discovery and Marauder will do about 625 fps average with 14.3 grain pellets. I was comparing these rifles to the Hammerli 850. Looks like for strictly CO2 usage, the Hammerli would make a better choice of rifle. I might try one of the PCP's a little bit later on when I'm able to handle it better. Right now the less effort the better. Thanks for the replies friends!