What brand of air rifle has a squirrel logo?

I'm not sure if this is what you are looking for, but Airforce Airguns uses a squirrel in their adds. He's wearing a helmet and holding an acorn with the Words "Protect your nuts" below him.

You can find him in almost every AirForce airgun add.

Airforce Airguns makes one of the most powerful airguns around. They are in the PCP class of airguns. They are adaptable to 12 different barrels.