Look what killed Prime in the animated movie. I count six hits in the 'liver', starting with a spike, including a beam saber and pistol shots. And he didn't immediately die, he 'bled out'.
Against a RX-78? IMO he wins. Prob even with a newtype pilot since he has instant response time.
Versus something equipped with a Trans Am, Psycoframe, fin funnels/bits or "we spending our animation budget on dis shit" beam cannons? Sorry my dude, you ain't it.