Is it right that a bullet with larger meplats will produce larger groups than those with smaller meplats?
Yes, pending yardage and loading recipe.
Is the Lyman 427098(Old standard 44-40 rifle bullet) better for ranges between 150 - 300 yards?
yes, more aerodynamic right?
What is with the Mav Dutchman 44-40 bullet with its larger meplat?
I don't know, guess the designer needs to answer that one....but it makes one hellofa self defense projectile.
I read it is an excellent bullet for CAS!
Yes, because of lots of lube the barrel stays clean for the day and it only travels less than 10 yards in CAS. Flat points also act similar to hollow points when it finds it's target. 45 Colt flat nose will knock the daylights out of ya if ya get hit with one!
Is there any empirical values with different bullets at ranges from 150-300 yards?
Sometimes it makes me wonder why big game projectiles are small and pointed...but then again, there is BPCR with round noses!
Hunting: Aerodynamics for distance, penetration then expansion.
SD: Penetration/expansion
CAS: to be able to shoot 100 rounds of ammo without having to swab the barrel....and hit a 24x24 target