By no means am I an expert. However, I just got done reading Ken Watters Handload book, and the advantages of the 7-30 over the 30-30 are about the same as the 7-08 over the 308. Better downrange ballistics in the form of better energy delivery, sectional density, and less recoil. The disadvantages now are that there is only one or two bullets made for 7-30 and that nobody makes the gun (lever action). It uses a necked down 30-30 case. I am sure that many would enjoy this cartridge, but the availability of cartridges, bullets etc. eliminates those who realize that advantage. Those that relize advantage of 7mm over.308 will probably pursue other calibers more efficient yet. Namely those that are pointed, and not rounded.