Mac1 Airguns makes several unique custom airguns and accessories; I’ve had experience with two. The first was his customization of my Crosman Mark 1 CO2 pistol, one of many airguns I wish I’d kept. The other is his “steroid” conversion kit for Benjamin and Sheridan pump rifles. It consists of a stronger cocking lever and link, an improved valve, an adjustable pistol, and a few other parts, and makes the converted rifle capable of something like 50% more muzzle energy.
In the photo above, taken around 1998, I’m shooting a .22 caliber Benjamin converted by Mac1. This was a review loaner for an article in U.S. Airgun magazine. The gun also had a forward scope mount to which was attached a Burris pistol scope, creating a sort of pneumatic Scout rifle. I wrote that it was an excellent gun, and maybe the ideal survival air gun: Rugged, easy to maintain with a few hand tools, and entirely self contained.
I still agree with what I wrote back then. It may take a while to pump up, but you rarely get a second shot hunting small game. The gun was capable of over 25 foot-pounds of muzzle energy with ten pumps. A conversion kit will cost you around $100 today, which is not much considering how much it improves the gun.