Dragon Ball has been just inconsitant enough with tech to make this up in the air.
On one hand, an average saiyan, if we say its between Raditz and Vegeta at that time, but closer to Raditz, and not having planet killer attacks, well...
Goku as a child took on the Red Ribbon Army. So yeah, a generic Saiyan soldier can handle conventional military might from earth with ease and then some (specifically, Dragon Ball's earth, which has more advanced tech than ours because Red Ribbon is like that. Bazookas and missiles don't seem to phase Goku by any particular level).
However, we also have Super, where a concealed alien weapon, likely the series' equivalent to magitechnology, can grievously injure Goku after he powers down. And this is, well, in Super, when Base Goku is far beyond "run of the mill Saiyan" even in his base form.
So what does it come down to? An interpretation of the rules of technology and such.
Commence your arguments on tech in the Dragon Ball setting. They are sometimes useless. But when they have actual "ki" energy built into them, they can assassinate a "Saiyan God" that has powered down.
I am the Hunter of Topics. My post never fails to kill its prey.
*pounces* Nyaa!