Sorry to be slightly defensive but...
After recent threads where it seemed the goal was to attack and argue.... I did not say exactly 400 yards I said approaching or exceeding. So...
Using JBM Vital zone of 5", so smaller than minute of pie plate. Elevation of 75 ASL as that is where my range is. That way MOA or less is still within the kill zone.
These are 3. I have others I can make loads for that reach that point blank goal.
300 RUM, Cutting Edge C48 180grains, IMR7828 at 3330 fps. gun)Max point blank 411 yards
300 Wby, Cutting Edge C48 180grains, IMR7828SSC at 3150 fps. lightbulb Max point blank 390 yards
270 Wby, Barnes TTSX 95, IMR 7828SSC at 3668 fps.
Max point blank 404 yards but this rifle is becoming a 338 Edge/Hart/338-300RUM.
Now if you are serious and weren't being flip to start an argument: I am keeping consistent in my approach to the use of monometal/copper bullets. Go lighter, go faster. They do suffer velocity/trajectory decay faster than jacketed bullets so, long range for me starts where compensating for that decay means multiple MOA hold over or turret twiddling. Max long range I am looking at for each caliber is one turret revolution, just me so I don't loose track.
Foot notes:
The point blank numbers are pretty close to the CEBS for TTSX 180s. Less than 10 yards shorter.
Unusual for me, the CEBs and TTSX are well withing book load ranges. More usual is to go closer to max due to pushing the COAL out longer than book.