Follow the original developers build instructions. I scaled up to 102% for my PSA AR15 BCG. Fit perfect. I recommend making the 10mm slice of the middle of the case prior to printing the whole thing as a size check on you BCG. I also made sample slices of the cap and top with threads to make sure I liked the fitment prior to printing. I used a few pieces of black leather I had to create a soft padding for the BCG as well.

Remember… “Success is in the details. Take your time. Produce a quality product you are proud of.”    - Travis Howell