I wanted to hunt deer with that bullet in my 7x57s, but neither one of them would group them worth a darn, but this is what I know about the bullet.
Silhouette shooters needed a tougher bullet on the rams so Nosler used the 140 grain jacket blank stamping. The 140 grain jacket doesn't get drawn out as far while being formed because the 120 grain is shorter, thus result is a thicker, tougher bullet.
