Left to right: 300wsm, 7-270wsm, 7 rsaum, 7-6.5prc
In the past six months, one of the most requested cartridges for new builds, has been the 6.5 PRC necked up to 7mm (7-6.5PRC). So let's texamine if this new wildcat is something that you should consider.
It seems to me, that we have gone a full circle. The 7 RSAUM gets necked down to 6.5mm, the neck gets little shorter, the body gets little slimmer and the 6.5PRC is born. Now, we are taking this "new" cartridge, and we are necking it back up to 7mm! Why? The short answer is brass. As we all know, Lapua makes overall the best brass. Lapua and Peterson made 6.5PRC brass is readily available while 7saum brass is either hard to find, or it is not of good quality. RSAUM brass is made by: Remington- super soft, and inconsistent in weight and quality. Norma-good quality but on the soft side and hard to find. And then we have -ADG made brass. Very well made/uniform, able to withstand high pressure loads, but kinda expensive and hard to get.
Both the PRC and the SAUM can hit the upper accuracy node of the 284Win improved variants such as the 284KMR and 284 Shehane with ease. The PRC has a little advantage when it comes to speeds between 2920-2950fps due to its slightly smaller case capacity. The case fill and the pressure generated, seem to be ideal for such speeds. The RSAUM seems to perform best around 3000fps. I have had quite a few SAUM barrels, and they all shot good at that speed. I must say though, anything over 2950fps was pretty hard on the Norma brass.
Bullets, primers, powders:
Berger 180, 184 hybrids and 180vld are proven to be the best bullet for both cartridges.
RE16, RE 23, H4350, H4831SC, VV 160, 165, and the new 555 are all good powder options.
Primers: best by far are the Russian Tula KV 7.62N aka Wolf
Federal 210M, 215M and CCI BR2 are also good.
So, should you switch from a 284Win to a 7-6.5PRC? I'd say yes, the PRC will give you better ballistics, with not much more recoil. Brass is easy to find and seems to last for several firings.
If you have a 7saum, or a 7-270wsm and have plenty of good quality (ADG or Norma) brass, then in my opinion switching to 7-6.5prc doesn't make any sense. After all, there's absolutely nothing ground breaking in the design of this cartridge. The improved versions look interesting , but not enough in my opinion to justify the cost of dies barrels and time.
Just my few cents