7MM is only a reference to bullet diameter which in this case is .284. Which 7MM are you talking about? There are a plethora of 7mm's available. The 7X57, 7MM-08, 284 Win, 280 Rem/7MM Express, 7MM Rem & Weatherby Mags, 7MM WSM & SAUM, also the Rem Ultra Mag. There are others that exist as wildcats.