I'm thinking the easy solution here is a plain vanilla 243 running 55BTips. It's easy enough to hit 4000fps, or even 4200 if you want to step on it.
Why bother with necking down????
Good point.
Seafire,
The 243 win has a case capacity of 54 grs, the Swift is 48.
Max loads in both 22/243 and Swift about 1250 to 1500 rnds barrell life as in any caliber that hits 4K+ IME.
The Lazzaronis have a barrell life of 750 rnds per the builder if loaded to spec.
Swifty
