If I've learned anything while wildcatting around the gun world, it's that somebody has done pretty much everything you could ever imagine, and then some. If that's what you want, find a good gunsmith, send him a signed, blank check, and be prepared to wait for a while.
I have had a 6.5x55 ackley improved (40 deg shoulder) for a year. Redding sells the dies in their custom section but they usually have a set or 2 on the shelf. It is a sweet shooting rifle. I had a new 260 barrel re-chambered for my Thompson Encore.
Do a web search on "6.5x55" and "Bob Jourdan". Jourdan developed his improved case following Ackley's guidelines in the early 1990s. He wrote up his work and published it in several issues of Precision Shooting in about 1993.
Your web search should produce a phone number in Oklahoma. He's a nice guy - call him up and talk about it.
A forum community dedicated to Sport shooters, owners and enthusiasts. Come join the discussion about optics, hand casting bullets, hunting, gunsmithing, styles, reviews, accessories, classifieds, and more!