Aaron hipp has one built already. He did some testing as is as follows
Some of you may know that I had a reamer made to neck down the new 300PRC to 7mm to see what it would do. I.e. A 7-300prc . I got it back from Alamo Precision Rifles on Friday and was able to put about 30 rounds on it so far and the results are impressive. The case is minimally larger than the 28 nosler but the shape and length provides some added benefits imo. Speed wise it seems that's it's can easily crush the 28 nosler with less effort and lower pressure loads. The 28 nosler advertises it can run a 175 around 3125 and I'm pushing 184 bergers at 3175 with a slow powder and zero pressure. Barrel isnt even broken in yet. I played with it a bit yesterday using retumbo and 8133 and with 82gn 8133 which is a slightly compressed load, Im at 3173 avg with an SD of 4.5 with 184 hybrid. Barrel is a 28" Hawk Hill Custom
No pressure even with water test. For those that dont know, the water test is pouring water on the case to simulate shooting in rain and if you have a hot load you'll blow primers and get a locked up or hard to open bolt in a heartbeat. I had zero issues and it opened like a normal round. Retumbo is faster still no pressure. This thing is crazy and stupid light recoil for the speeds. My original goal with this was to push a 180 pill at a mild 3100-3150 with a powder that gave me almost full case fill and no pressure and it seems to be working spot on for that. Ill post more as I keep testing. Today will be a brass life test and temp sensitivity test. I think with something like RL26 or H1000 you could probably push a 180 in the high 3200s to mid 3300s or a 195 around 3200 without being too hot of a load.
Update 1 - 7x firings with 81.4 of 8133 was averaging 3155 with the 184. Everything felt good until the last resize and primer went in pretty easy. Checked the case and saw the faint line of death around the base. Checked the inside and you can feel it getting thin. I wouldnt push it past 5 to be safe depending on your load.
Also realized the Hornady 300 PRC sizing dies are no good. They dont size far enough to the base at all even if you push a piece back to factory dimensions. Hornady you better check your PRC dies or you're going to have a lot of people pissed off they have a sticky bolt on any reloads because your dies arent sizing enough. They arent even changing the dimensions of the case anywhete close to the base from a fired piece to resized . I thought they were sizing way to easy for such a large case and now we know why. They need fixed ASAP.
Update 2 - Between the seating die being a bad design imo which also doesnt work with a Forester Co-AX without chopping down the seating stem, the fact that the sizer doesnt size properly or that the hole diameter for the bushing is massively oversized and causes crazy amounts of neck runout unless you teflon tape the bushing, I'm done with the Hornady "Match Grade" dies. Unfortunately they were the only ones making PRC dies when I needed to get them. I'll probably give them away at some point or maybe do something really silly with them out of frustration. I spoke to Dan Warner today at Warner Tool Company and I'm going to have him make me a set of custom dies. If you havent seen their custom dies, they truly are a work of art with no comparison. I've been considering a set of his dies for a while now and finally going to pull the trigger.
