I was lucky enough to be asked to section this round. Had it been in my collection, it would still be whole!
Falcon - The finish was done by sandpaper. The only power tools I use are a Dremel and belt sander (for the larger items). Everything else is done by hand.
Alex - Sorry, I did not record the case length. Perhaps the owner will post the information. From The SPIW book, the total length given is 3.83" (97.3mm), but the projectile does protrude from the case mouth.
Vic - The folded chamber does expand and occupies more than half of the case volume once fired. Recoil is probably about the same as the M203 mounted on a M16A2 (i.e. the weight of the weapon platform is going to be comparable), but without the noise and flash when fired.