Hot on the heels of my weight calculator comes a balance calculator, which will tell you where the center of gravity of your AR is. Right now it doesn’t have nearly as many components as the weight calculator, but I’m continuously adding more. It’s meant to give you an approximation of CG, because to be exact would require knowing the CG and exact location of every component on the rifle, but it has proven to be quite accurate, within .15″ in almost every case, and within .05″ in a large portion.
This is cool, but it doesn’t seem to actually report negative values, just a minus sign in its place. Also, it seems like this could be easily added to the weight calculator so it would report both after you give your specs.
What combination are you trying? I see negative results without any issues. I will fix the problem if I can. Also, what browser/resolution are you using?
Interesting. I was using Chrome on OS X, and I just tried on Safari and Firefox (also OS X) and it works fine. I guess Chrome’s Javascript library isn’t playing nicely with your code.
FWIW, my combination was CTR w/ buttpad, lightweight carbine barrel, and single-shielded handguards (that’s the closest to my setup right now given the limited choices).