I've been considering building a 300 win mag for a long time but when the 30 nosler came out I started watching and now that the 300 PRC is out I really don't know which to choose. Ballistically they are all close enough that the edge goes to the one in the best rifle, factory win mag ammo has to fit in factory win mag chambers and so on so assume all rifles have the same barrel and the win mag has a improved throat for heavies. in this scenario I don't see these cartridges running factory ammo much but rather all 3 shooting the same bullets so the only cost differences are in the brass, there's cheaper win mag brass out there than the PRC and the Nosler is the most expensive assuming all shoot Hornady brass because they are the only manufacturer making all 3.
all 3 cartridges will group close enough to the same in good rifles and for magazine fit purposes length to beginning of the neck is
Win Mag - 2.356
PRC - 2.2724
Nosler - 2.246
which means you can load the longest heaviest bullets in a 30 Nosler in a magazine but only by 0.0264 when the same bullet is seated with the same amount of neck contact while eating the same amount of case volume. they will all feed with the same bolt from the same magazine length from the same action length.
As far as comparing loads I don't see much point in lighter stuff as nobody will buy these to torch a barrel with 150gr bullets at varmint rifle speeds so lets look at what you can expect with whatever 200gr loads I could find.
Win mag - 2923 at 3.34 coal and 79.9 gr of Magnum powder in a 24" barrel (Barnes Data for LRX)
PRC - 3025 at 3.575 coal and 78.3 gr of RL-26 powder in a 24" barrel (Hornady data for ELD-X)
Nosler - 3080 at 3.34 coal and 83.0 gr of Retumbo powder in a 26" barrel (Nosler Date for Partition) - correct for barrel length if you want to play fair
the next step is 220 gr loads and you get the following
Win mag - 2771 at 3.34 coal and 74.5 gr of RL-26 powder in a 24" barrel (Nosler Data for Partition)
PRC - 2875 at 3.585 coal and 78.1 gr of Retumbo powder in a 24" barrel (Hornady data for ELD-X)
Nosler - 2981 at 3.34 coal and 81.5 gr of Retumbo powder in a 26" barrel (Nosler Date for Partition) - correct for barrel length if you want to play fair
This isn't really apples to apples because Hornady uses longer COAL for their published loads to get a little more out of them and Nosler uses a 26" barrel to do the same cheat. it's obvious that they are both hotter than a 300 win mag and all things considered the Nosler is going to be hotter when loaded to the same COAL with the same bullets because it has the volume advantage but that comes at a cost of $0.020 per new brass and $0.035 more of Retumbo per shot. average that to lets say half a dozen loads per brass(conservative but these are magnums with Hornady brass prices and no history yet) and you will pay about $70 more per 1000 rounds to shoot the Nosler over the PRC.
I'm not arguing for the PRC or the Nosler but when it comes down to it the Hornady Engineers appear to have looked at the 30 Nosler and said "lets do it a little cheaper"
