They share barrels but the A7 comes in 2 different action sizes whereas the the T3 has only 1 action size. The A7 has a metal bolt shroud whereas the T3 has a plastic one. The A7 has metal feed lips on the magazine whereas the T3 has plastic.
The T3 has a very stiff action because of the small ejection port which can be both a good thing and a bad thing.
Given the prices of the A7 and the T3 I think the A7 is a better value.
