Board Thread:Off Topic/@comment-26397825-20160609071212/@comment-27144409-20160624214856

You can still totally try for a 30mm. It would just be a challenge. There are real man-portable 20X102mm rifles currently available for sale to civilians IRL. A 30mm weapon in Remnant is plausible.

I don't know what you're doing so start with your original 30mm idea.