Kobuku68, I have heard the same thing about the 220 in the 3003. It prevents or lowers the risk of damage using the shorter brass.
I also have a friend that says it was the projectile of choice 4 the 30/40 Krag?
All I shoot out of my Krags and they are deadly in my Win 1895 SRC.
The .30 US Army was simply made for the 220 RN.