So this may be a bad idea but I have been thinking about trying to design a new wildcat rifle caliber. I have heard of people creating their own one of a kind rifle calibers but I cant seem to find much information on this topic on the internet. I was thinking of using a 270 cal. bullet in a large case such as the 338 lapua mag. I dont know if something like this has already been done or if there is a reason it has not. with the large case and fairly small 270 cal. bullet i would expect it to be an extremely fast round (maybe too fast). I would like to do this just for the challenge im not trying to get certain results out of this new cartridge. If anyone knows anything about designing new cartridges any help and knowledge would be appreciated. As of right now i Know very little about this subject and of the work that goes into doing this and now it is more of a hypothetical thing until I can get a sufficient amount of info.