Ok say the NPC or PC attacks full auto and they score a hit.

Let's say the weapon does 1d10+4 and the full auto is 8. Does that mean they score eight hits with 1d10+4 damage?

Sorry need clarification on this one.

Full auto gets you one hit per degree of success. So if you had 5 degrees of success you'd score 1d10+4 five times. Each hit is reduced by toughness and armor.

It's also worth noting that full auto allows you to allocate the extra hits to targets near to the original target, so if 5 hits would murder your PC (very possible) you can put a few on the guy next to them.

The number under full auto (in your case, Full Auto 8) indicates the maximum number of hits the weapon can achieve. So a weapon with Full Auto: 8, can hit up to 8 times when fired on Full Auto, but that would require 8 degrees of success.

See: Full Auto Burst on page 221 of the core book for the rules.