Haugenna - all of them I have done so far have been hunting rifles. Most started life as a .300 Weatherby Mark V. One was already a .378 Weatherby. The 2nd one was a Remington 700 - which I'm not sure had been done before - at the time. The customer took this rifle to Africa and gave it to the guide as a tip after killing about 30 animals. I made him sign a waiver first - but it actually came out pretty good. Required an M-16 extractor and a custom magazine box. Several have been P-17 Enfields.

One thing I will say in favor of this caliber is that, with a 28" barrel, they can really stretch their velocity advantage over smaller .30 magnums. But a classic example of the law of diminishing returns at best . . . .