Isn't it? The quote I replied to was in reply to a comment saying that the 300wsm might be more efficient in a shorter barrel.That’s not what was being discussed.
It was mentioned the 300WSM could be more efficient in a short barrel which the above would all contribute.
Efficient meaning "achieving maximum productivity with minimum wasted effort or expense."
Powder and recoil being the expense.
I would say the extra powder in the 300WM giving very marginal gains would make the argument its more efficient by definition as is the case with many smaller cases ie 6ARC vs 6GT vs 6Creed vs 6UM representing modest improvements via significant powder additions.
Running the 300WSM vs 300WM with a 215 Berger in GRT at 18" with the bullet seated with the boattail at the shoulder junction in each (3.144" for the WSM and 3.7" for the Win Mag) and a load of Retumbo giving 65kPSI (76.3grains for the WSM and 82.6grains for the Win Mag) represent muzzle velocities of 2688fps and 2694fps respectively. Reference at 16" it has the WSM ahead by 4 fps and at 20" it has the Win Mag ahead by 14fps and 25fps at 24"
I would say that using 8% less powder for 0.2% less velocity makes it more efficient.
Anyway maybe its a skew as in NZ the 300WSM is far more popular in new rifles than 300win mag here which is effectively dead as people will just by a 300prc or the 300wsm instead of dealing with a belt. I'm not saying make a 300WSM instead but a 300WM seems pointless as a sku if 300PRC is available as i cant see a FUDD chambering being popular in a rifle as "progressive" for lack of a better word as and MRC in a Rokstok. Same reason they have said they aren't doing a 375h&h in the rokstok model.
I would struggle in anyway to say the 300 Win mag is in anyway better than a 300 WSM. But in all honesty I dont care as after reading all your evidence and the others on here I've been running a 223. As it confirmed what shooting Kimber's taught me which is that recoils not your friend and that small calibers still kill great at reasonable hunting ranges.
Just a discussion and happy to be wrong but from what I have seen in running a lot of short rifles which are super common in NZ from 12" and up since suppressors are so easy and cheap to get. I have 100% seen there is a point at which you simply get very minimal return without large increases in powder. GRT and Quickload backup that experience. I've not shot as much as you but I have run a lot of rifles with 16 and shorter barrels.