Pete, I have a Complete No4 action, and two No4 receivers that I'd like to use up. All are of the MkI* variety. I also have two No4 barrels, not attached to anything, that can be rebored to larger calibers. It makes sense to work with what I've got.

The .375 is of most interest to me right now. I'd really like to hear from others with experience with it. An alternative is to chamber for the .375/444. It is supposed to feed well from a standard .303 magazine, and delivers more power than the .375 2 1/2-inch. There are references to it buried here in various forum archives.

I have pictures of Lee Speeds with solid steel butt plates, and others with trap door butt plates, much like the military items. However, the trap door butt plates have more of a sporter shape, tapered toward the toe. I'm wondering if a steel military butt plate could be modified to the sporter shape. A solid steel sporter butt plate isn't a problem.

One of my projects is a 35/303. In a practical way it is as powerful as a .375, delivering a 300 grain bullet at 2000 fps, compared to a 270 grain bullet at 2000 fps. I'd like the .375 just for fun, but I want it to be nice, like a Lee Speed.