The biggest advantages of the Avenger are the side lever cocking, the adjustable regulator, and the weight (2 lbs less). The gauntlet has a preset regulator at `1900 psi and the gauntlet 2 is at 2100 if I remember right. The Avenger can go higher, as high as 2900 but I don't think settings above 2400 or 2500 will do much for you. But still higher. The Gauntlet II adds say it will produce 51 ft lbs, that is the same as my 25 Avenger does with it's current 2400 psi 1.5 turns in tune using JSB Heavies. It puts them into 1/4 inch groups at 33 yards with regularity. I am waiting to get my SCBA tanks setup done to take it to a range and try all the pellets it does well with at 50 and 100 yards.
If you are hand pumping, you might want the original gauntlet. I hand pumped my Avenger at first but it was 250 pumps to get from nothing to 3500 psi and a typical refill was 100 pumps. I bet a Gauntlet is less. A Gauntlet II probably gets more shots on a fill than an Avenger, it's tank looks bigger but I did not compare specs. If that is right and the Gauntlet II is a bigger tank, you may not want to hand pump it. But in terms of pumps per shots I'm guessing either Gauntlet has an advantage.
I have only tried 3 slugs so far but my Avenger did not like any of them at all. Others report much different results and I may try some NSAs before giving up. But I also question the role of slugs, at least for me. The ones I've shot expanded nicely in wet paper but didn't penetrate nearly as well as domed pellets. The slugs penetrated about as well as 22 caliber domed pellets out of my Prod. So I could could use them on squirrels and make bigger holes through them but the squirrels die quickly from 22 caliber domed pellets - they drop on the spot with a hit to the vitals. So a 25 caliber hole should be plenty. A little less drop and more significant difference in wind drift are advantages but overall, I'm still struggling to see where I really need to shoot slugs. But it's fun to mess around and I will probably do more.
