Would you be able to feel a pulse during atrial systole only?

No, you would not be able to feel a pulse during atrial systole alone. A pulse is felt when blood is ejected from the heart into the arteries during ventricular systole, when the ventricles contract and pump blood into the aorta and pulmonary artery. Atrial systole occurs just before ventricular contraction and primarily fills the ventricles with blood, so it does not generate the pressure wave necessary to create a palpable pulse.