500 MDM Terminal Performance
When I designed the 500 MDM my goals were to equal or exceed the ballistics for 500 Nitro. Although I never owned a 500 Nitro, being a rimmed cartridge designed for double rifles, I always considered a 500 Nitro "King Of the Hill" for terminal performance in the field on the heavies, elephant, buffalo, and hippo! With the right bullet design, the 500 Nitro cartridge has perfect ballistics for this sort of work, a 570 gr bullet at 2150 fps will do any mission on earth asked of it, and do it very well! This was my goal, only difference, the big RUM case, .500 caliber, and a bolt action rifle that comes in at 8.5 lbs with a 21 inch barrel. For that I had 550 gr bullets made by SSK for the 500 MDM. I exceeded my original goals and we are able to run that 550 at 2200 to 2250 fps without much of an issue.
But I must be honest with you, I have learned that it just is not necessary to run a 550 gr bullet in these guns. In my more ignorant days, sectional density still had meaning, today it has less and less importance and bullet weight and sectional density is becoming a moot point. A proper designed 500 gr solid bullet drives just as deep and straight as a 550 gr bullet. One might gain a couple of inches or so with the 550, but over the course of 5 ft of penetration, a couple of inches is truly not important. So I have elected to use 500 gr solids in the 500 MDM for myself at a sedate 2200-2250 fps and get excellent performance from this.
When I first used the 500 MDM last year in Australia, before the first buffalo I had decided that I really should have had a heavier expanding or Non Conventional bullet at 500 grs or so. Still, from years of having sectional density mean something I thought my 470 gr copper HP was not heavy enough, maybe I needed more weight for deeper penetration. Well, wrong, after seeing the performance of the 470 gr Copper HP on buffalo, and getting through and through penetration, and EXTREME TRAUMA inflicted, the thoughts of needing a heavier expanding or non con completely disappeared. With proper bullet design, throw sectional density and conventional wisdom out the window!