I've been working on an actor with a much higher mass so he can wield bigger weapons with less recoil since I greatly enjoy weapons that shoot high mass low sharpness bullets
However, being pushed at all makes him explode (i.e. being slightly touched by an impulse grenade and he gibs spectacularly)
Is this intentional or is there a variable I can modify to make him not do that?
I'm trying to make him more resilient but not god mode, I have enough of those already

Have your gun(s) shoot an AEmitter that then shoots the high mass projectile. It removes your actor from the recoil essentially.

Higher mass on your actor will come at a cost of terrain rape and making your jetpack nigh-useless.
If you want a more durable actor scale up the GibWoundLimits and GibImpulseLimits, and/or change the material it's made of to a stronger one.

But I like that he's heavier, it's more interesting than just making him eat more bullets
The gun thing is complicated and I'm lazy and the only weapon I have that uses it that I could copypaste is shook's Plasma Cannon and there's a lot of extra effects that go into it
I made a jetpack that works pretty well for him
I did change the material, so that's not a problem

I might be wrong but I think making the join strength on all of his limbs and attachables would fix the problem you are having