ZDoom

i would like to see gibbing with ssg like in smooth doom

Features that can be accomplished with modding are rarely done in the engine. This enables modders to create these things themselves, while keeping the engine stable and flexible, and also keeping it as efficient as possible at the core. Therefore, suggestions like this often get rejected because the ability for you to do this is already there. I suggest asking in the scripting forum or joining the Discord if you need help knowing where to start.

if you're referring how:

to make the SSG to forcegib enemies, you should make SSG use the A_FireBullets function (https://zdoom.org/wiki/A_FireBullets) and make a puff actor with the +EXTREMEDEATH flag (https://zdoom.org/wiki/Actor_flags#EXTREMEDEATH) enabled to force actors to gib.

tl;dr make a weapon actor that fires fires gibbing bullets