does anyone have precise measurements for the XM732 6mm x 45 SAW ball projectile? i am attempting do determine the ballistic coefficient and am reluctant to pull the bullet on one in my collection. an original drawing would be great, thanks!
While it is possible to calculate a ballistic coefficient based on the bullet’s diameter, weight, and radius of the nose ogive (and there is free software available on the internet for doing that), it would probably be about as accurate (if not more so) to look over the various bullet manufacturers’ web catalogs of available 6mm bullets of about the same weight having a nose of similar appearance (or of the same bullet length) and use their published coefficient. It does make a difference if the bullet is flat-based or boat-tailed. So you would also need to know that, which, if you do not, might require pulling the bullet to find out. That can be done without damage by using an inertia bullet puller, then re-seating it. That would allow precise weighing of the bullet (and case & propellant), and would also facilitate making dimensional measurements if a bullet drawing cannot be found.
Determining the bullet’s coefficient experimentally is not that difficult, but you would need a supply of shootable ammunition, a rifle, and at least two chrongraphs. Not likely that you have those. Note that BCs are not constant for all velocities, and BCs are often given for several velocity ranges.
Could be that BC and dimensional information is available in some publication somewhere, but I wouldn’t know where to look for it. I bet someone on this site knows all about this bullet.