In several .270s, the Hornady 110gn PSP turned out to be the most accurate of all the light bullets. Read more
BM 8208 is a small, short-grained stick powder specifically developed for varmint and benchrest cartridges.
The .222 Rem. Mag. has 20 percent more case capacity than the .223 and delivers 100-150 fps higher velocity.
Is there a barrel contour (octagon, fluted etc) that affords better accuracy?
I suggest you use Federal 205M primers in your .204. I've never had to resize the primer pockets in any cartridge I've reloaded for.
The action of your Remington rifle in .308 is too short to be rebarrelled to .257 Wby Magnum.
I am at a loss to explain why the 7mm WSM didn't become an outstanding success
The .280 AI gives magnum performance in a standard rimless case and I'd rate it as Ackley's finest wildcat.
Forming cases is as easy as falling off a log. Simply run 7mm SAUM cases into a full length die, trim to 2.025" and deburr case mouths inside and out. There's no need to ream or turn case necks.
Any damage to the bullet's base, however, does have an adverse effect upon accuracy.
Under favourable conditions, they often kill deer cleanly enough, but conditions are not always favourable in the field.