Well I guess the only way to find out is to ask them what they are basing in more on. TT or Black Library novels.
You aren't already? Your Avatar is double fisting a bolter and a thunder hammer. Seems pretty BA to me!
To clarify what I mean, it works in table top because you don't really find out where you got hit or what happened all you see is the roll. It works great in the pen and paper though because you have localized damage and you know where it hits say if they don't have any leg armor their leg will get severely crippled whereas a chest shot wouldn't really do anything). It's hard to balance but I understand why you want to go down that route.
You are deluded by your propaganda, mon'keigh. I see the sheer surprise in the dying eyes of your kin every time. I so much hope so...
Is it impossible for a single Ork Boy to kill a Terminator in the 40k universe? No. But it's so incredibly rare and unlikely that it's not even worth mentioning. A Terminator is going to be easily dropping Orks left and right in almost any situation. I'm stating the balanced tabletop game rules from the source material is not an accurate representation of what happens in the 40k universe.