Your proportions are way off and like Panda mentioned you will need a high poly model in you want to make high quality weapon models.Take a look at these tutorials:…
You're gonna want to read this to udnerstand how to integrate Boolean modeling into your high poly modelmaking https://polycount.com/discussion/168610/3ds-max-zbrush-proboolean-dynamesh-hardsurface-workflow-tutorial
Hey thanks, I've done a little bit with booleans in Blender but haven't even opened Zbrush yet so I'll definitely give it a read. I've been trying to get into as many tutorials as I can, using google and youtube like a mad man.
I appreciate your input, thus far i've been doing everything in Blender 2.8 and Substance painter. I think ill do the tutorial you linked from flipped normals, though using Blender instead of 3DS Max, for low poly, Zbrush for high poly etc. See what I can come up with.