Re: Understanding the 6.5x 284 Norma Caliber
As stated, the '284 Winchester' is necked down to hold a 6.5mm bullet and is called the 6.5x284. Kind of like the 30-378 WBY. 378 WBY case necked to 30 caliber.
If you're considering an f class rifle, more and more guys are moving away from the 6.5x284 due to barrel life. Many have moved to the 260 Remington which offers only a minor amount more windage than the 6.5x284 but offers more trigger time with added barrel life. Many are also finding the original 284 win is a better alternative as well. A slight advantage in the wind with better barrel life. A bit more recoil but everything is a trade off.
Personally I'm using a 29" 308, 11.25x 5R running 190 VLDs at 2750. About the same wind as the 260 rem with a lot better barrel life. Many say that barrels are like tires. When they wear out, replace them which is true to a point but its hard to see your 'hummer' barrel deteriorate so fast. Some barrels are real gems. It's a shame to ruin them with barrel burner cartridges. Tires don't have personalities like barrels do.
Long range shooting is a process that ends with a result. Once you start to focus on the result (how bad your last shot was, how big the group is going to be, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.