Below are some comments from the Tromix demo shoot in Missouri which were posted earlier on Bower's Subguns.com board.

"Tony Rumore of Tromix was at the Lebanon, MO Shoot & Show today demonstrating his creations, including the .458 SOCOM cartridge and some M16's chambered for it. On arrival, we thought someone was firing a cannon, judging by the blast felt from well behind the firing line, but it was just a Tromix M16 with a 10.5" barrel opening up with full-power .458 SOCOM loads. We heard a throaty, low-pitched BOOM, B-B-B-B-BOOM as fireballs at least 3 feet in diameter appeared downrange of the muzzle. Tony was kind enough to let some of us run through a mag full of these monsters. Quite a handful to say the least, but pure loud fun. No malfunctions of any kind despite a cartridge so big it completely darkens the door of a factory M16 mag. Single stacked, these wide boys use up all of the space available in a magazine. After all that sound and fury, the quietness of the subsonic load, even unsuppressed, caught us by surprise. Turns out that the selection of projectiles in .458" is fairly extensive, including 600 grain missiles. Cases are proprietary, as no suitable parent cartridge offers a long enough case. Ever wondered just how much power you could get out of an M16? Thanks, Tony!"