Just saw this, not sure if I can help or not, but *think* I understand what is going on.
Originally I had contacted Weatherby, but they were not offering a magnum bolt in a short action, and I think that was 2-fold. 1) the 6.5 Weatherby RPM is very similar to the 6.5 PRC, but it uses a standard bolt face rather than the magnum, and 2) The 6.5 Weatherby RPM is a long action cartridge. Recently they started to offer a magnum bolt in the short action, on the Weatherby site.
I am not sure I should mention this, but PTG had a great sale recently that is still going on. The reason I say I'm not sure I should mention it is that a lot of people detest PTG, but I have several of their bolts and while they're not fast to ship, but they do ship the stuff eventually. Currently they have a $500 sale on a blueprinted Weatherby 307 action, it's blueprinted by Pacific Precision Grinding and Machine.
www.pacifictoolandgauge.com
They have another sale going on, but not sure for how long...you get a barreled 307 action with a rail, trigger (either Timney Impact or PPG worked X-mark) for $750.
www.pacifictoolandgauge.com
I ordered a barreled action, as PTG is doing it with a magnum bolt. For the action, they wanted $225 to add a magnum bolt, but for the barreled action they said they would do that. Comes out to almost the same price as just the action + adding the magnum bolt.
DISCLAIMER: I am not affiliated with Pacific Tool and Gauge. The lead time is 1-12 weeks. They do have long actions, and it's worth considering a long action magnum, Weatherby has always done those, but I have an ACIS 1.5 chassis with viper skins in short action with 2 x 5 round mags, and although it is heavy, I will pickup a MDT LSS Gen2 chassis in the future, as it only weighs about 1.7 lbs.
I like the 6.5 Grendel, but honestly it doesn't hold a candle to the 6.5 PRC and I can shoot the same bullets in 6.5 Grendel, 6.5 Creedmoor or 6.5 PRC, mostly Barnes 127 grain LRX, 120 grain TTSX, 120 grain TSX, I have all of those. 6.5 Grendel is adequate for most hunting I will do, but I feel safer hunting black bear with a 6.5 PRC. I like 308 also, another fine NA game cartridge, but the 6.5 PRC gets the best ballistics and biggest bang for the buck in a short action. For long action I would look at 300 PRC or 7mm PRC, but a 300 PRC would be a heck of a hunting rifle.