What is the best pellet gun for shooting small varmints?

There are several available. The most common are and readily available are made by Gamo and Crosman. But there are over 100 different manufactures. Most are available on the web. Any air rifle that fires above 800 FPS ( feet Per Second) will be sufficient. BUT: here are a few things to remember. Stay away BB guns and rifles or any combination of BB and pellet rifles. They are just not accurate. I suggest a spring powered rifle ( Break Barrel). These will be the most powerful. C02 rifles are fun but are not as powerful as a Springer. Pump rifles are good but you have to pump them 10 times to take a shot. The downside to a springer is you have to cock it every time you take a shot. But it is more effective for taking out varmints. Use hunting pellets, They Mushroom when they hit the target and will make a clean kill. If you can afford it select a .22 caliber air rifle over a .177 caliber rifle. It will have more knock down power than a .177.