Have never owned a Challenger, but one of the guns I most regret selling was a Crosman 157 (.177 version of the 150). It was the second version with heavy barrel and integral breech assembly, 2-level power adjuster, and the slab-sided white marbled grips. Got around 40 good shots out of a cartridge as I recall.Just a wonderful little pistol. Handy size, decent sights, predictable light-ish trigger, very comfortable grips in spite of the plain appearance, and very accurate. The hefty barrel made it a bit heavier than many similar designs, but with a nice muzzle-heavy, target-gun balance that I really liked a lot. A bit loud for my suburban back yard (main reason I sold it), but otherwise super.