After about a year and a half of using blender 3D I finally found the measurements system. Normally blender uses it's own units where one blender unit is equal to one meter sqaured. However most models are not scale to the actual scene it's encased in often making the measurements incorrect.
I finally foud the measurements though under world>units>Metric. However I found out one little annoying f**cking thing. Blender has two forms of scale/size. One scale for the 3D viewer, aka object mode. If you scale while in object mode there's a command that can clear the scale and it only effects the scale that was given while it was in the object mode setting.
And then there is edit mode scalling which is maintained regardless of object mode scalling.
Why does this all matter? On almost all of my projects I used a mix of edit and object mode scalling that fucks with the measurement system and fucks with the relationed size of all the compenants I've already made. So I'll probably going to be making several of my guns completly from scratch again however to a higher degree of accuracy. Luckily most of these bloody things take all of 5 minutes to really produce. But none the less it's annoying.
It's almost as annoying to spend a hour with a buddy making threads for a gun barrel to realize right after there was a "screw modifier" in the modifier's panel. All the blender users that watch me will know what I mean by that >.< [Don't say I told ya so Vicky]