No. Air pistols are not designed to withstand the pressure generated by gunpowder.
This is a .22 caliber air pistol not a .177 caliber pistol. See the link below for the owners manual.
The most powerful air pistol would be a Air Force Talon-p 25 Caliber. This is a PCP class air pistol. The air tank uses 3000 PSI to fire the pistol.
The Olympic air pistol and air rifle events use a .177 caliber pellet. The biathlon (skiing and shooting) uses a .22 caliber rim fire rifle.
The Benjamin 250 is one of three pistols that make up the 250 line of air guns. Here is how they break down: 250 is a .175 BB pistol 252 is a .22 caliber pellet pistol 257 is a .177 caliber pistol. The problem is finding .175 BB's today most all BB are .177 caliber. I've heard that BB are still .175 only the caliber of the barrel has moved up to .177 to accommodate pellets. I suggest you just try one.
The C-11 shoots .177 Caliber BB's not pellets
Benjamin made this model from 1946 to 1985, but did not start serializing them until 1957. I also have a Benjamin Franklin that has no serial number. Before 1957 it is not possible to set an exact date. Just know it's OLD. The 137 is a .177 caliber pellet pistol the 132 is a .22 caliber pistol and the 130 is a BB pistol.
Air Pistol, NOT Air Soft Pistol. Then I would have to say it's the Evanix Hunting Master AR6 by Evanix It fires a .22 caliber pellet at over 1000 Feet per second But's that's just my opinion. I think it would be hard to find another pistol that fires a .22 cal pellet that fast. See the link below
I would do a search on the web for "Air Gun Repair," there are shops that make a living repairing air guns. Or see the link below.
Considering PISTOLS ONLY, NOT rifles then: The Beeman P-1 is amongst one of the most powerful. But there are most likely others. But that is only in .177 caliber. Real power is in the PCP (PreCharged Pneumatic) air guns like the .25 Cal TalonP or the .22 caliber Marauder pistol. see the link below
In NRA terms, this is Air Pistol and Standard Pistol. These are types of pistols used in International style pistol matches. Air Pistol is usually a 60 shot slow-fire match. Standard Pistol generally consists of 20 slow-fire, 4 x 5 shots in 20 seconds, and 4 x 5 shots in 10 seconds (rapid rife). In addition, on my collegiate pistol team we also competed in Free Pistol (FP). That is for light trigger, single-shot pistols with advanced grips. SP and FP use .22 rimfire ammunition.
Most likely it would be the Evanix Hunting Master AR6 by Evanix. It fires a 22 caliber pellet at 1000 FPS. This pistol is in a class of PCP pistols. (Pre Charged Pneumatics.)
With enough money and a talented craftsman anything is possible. Any competent engineer will be able to machine an offset converter to allow the use of a regulator and air cylinder from a pistol such as the Rohm Twinmaster.