Call me stupid but......bolt on your excel spreadsheet writeup your measurements are in inches right? Well some of the pieces measure 6.3",7.2" 9.7" etc. How can you measure that way if inches are not based on multiples of ten. Shouldn't it be 1/2" 1/4" 1/8" 1/16" 1/32" etc. I know I'm probably missing something really obvious so please don't flame me for asking such a simple question but I don't understand, please help me!

Typically, drawings are done with dimensions in decimal form. Makes it less cluttered, easier to read, easier to enter into a computer, etc. On the excel worksheets I set 10 squares to an inch, to get the best resolution I could, making each square 1/10th of an inch. I used an engineering scale, which is in tenths of an inch, to measure the parts. This is probably foreign to most of you who are only familiar with typical inch fraction scales.

You can approsimate the length of most of the parts. Nothing has a high enough tolerance that it needs to be exactly the length specified. Some parts could and problebly would vary quite a bit from the drawings depending on your gun. Just use a fraction scale and approximate where the length will be. Remember 0.5" = 1/2" , 0.75" = 3/4" , 0.125" = 1/8" , etc