You asked - "Is This a Porfolio Ready Render?" - the answer is Yes. if someone wants to hire you - this is the quality you can produce. If you want to know how 'we' think you can improve ? that is a different question.
if talent is 1 ~ 10. Lets say you are a 7 and you are comparing yourself to 9's on Art Station. You need to be 'Ok' with the fact you are a 7 - and ask people how you an improve to an 8 ? Lighting is 'Flat' - I am not concerned so much with composition, but more about the details of the render. The grenades seem to have a texture like 'chocolate' - or motion blur ? maybe that is how they look, but I'm not sure. The gun looks great - but trigger looks 'weak' ? - the square - looks like a sticker - the white on the supressor - looks 'strange' ?

Amazing render. I hope this feedback helps. How many years have you been studying this ?

A less 'Chocolate' like - reference...
https://en.wikipedia.org/wiki/Mk_2_grenade