Do not select a .177 cal rifle. You will get better performance with a .22. Pellets for .25 and .30 cal rifles get expensive but deliver more energy if you need to address animals larger than rats.
I know, i read all about it last week. .177 bullets will fire supersonic and will be inaccurate when they become subsonic again.
You dont want the sonic transition, you want to travel the trajectory either subsonic or supersonic, so pellet weight must be adjusted to the guns energy. Meaning that you might use a lighter pellet on a higher power PCP to maintain a supersonic bullet trajectory, and uou might want to use a slightly heavier pellet on a lower energy rifle to maintain a subsonic bullet trajectory.
I am looking at the Gamo Magnum IGT gas ram, .22 caliber, 45 joule of energy. Its the most powerful breakbarrel on the market, and at this energy a 1 gram .22 pellet stays subsonic, so i can buy cheap standard pellets in town, instead of requiring heavy pellets or slugs to keep it firing subsonic. According to online calculators, 45 joule should fire a 1 gram .22 pellet at just over 300m/s where the sound barrier is 330m/s
Its much cheaper than a Weihrauch, and according to my hunting colleague, Gamo is just good.
I am just not sure whether i want the 10 round magazine or the manual loader. Keeping a tin of pellets at hand is always a PITA as you drop them so easily, but i dont know if the 10 shot magazine accepts any shape of pellet and how it holds up over time..