I am good friends with the principals of Lehigh Defense, an up and coming bullet/ammo manufacturer. I get the privilege of brainstorming and providing input with the R&D guys in coming up with new products.
Several months ago we started discussing the idea of a .475 caliber semi-automatic handgun cartridge. We ended up designing a totally new case to house the round. It is designed to be utilized in guns originally chambered in .45 ACP. Initial developmnet and testing has been done with a Springfield XD Tactical with the ONLY modification being a barrel swap. Factory magazines and gun internals are utilized with no tweaks or changes. This makes a truly versatile switch caliber package. XD Barrels are going to be available directly from Lehigh.
Lehigh has also developed 2 proprietary bullets for the cartridge. The first is a copper 200 gr. (CF) Controlled Fracturing bullet which sheds three 35 gr. petals upon initial expansion leaving a .475" 95 gr solid base for deep penetration. The second bullet is a solid copper 220 gr penetrator. Most other factory bullets under 400 gr. should work in the cartridge as well.
Testing with the CF bullet has shown dramatic, devastating performance. With the 200 gr. bullet running right at 1200 fps, initial expansion results in violent energy transfer with the razor sharp petals doing massive tissue damage. The 95 gr. base keeps tracking in a straight line demonstrating 16" of penetration in 10% ballistic gelatin. The attached video link shows a test shot into the gel. Watch the upset of the front block. We were also firing .300 Whisper rounds the same day and the gel blocks would barely move with those. But with the .475 Lehigh shot the front block nearly flips over and is cut almost completely into thirds.
I have no vested interest in the company other than I'd like to see my friends do well. I just wanted to post on here because I thought some of you my find the cartridge interesting or useful. It sure was fun being the co-designer of a totally new cartridge. I could get hooked on that!