MagnumManiac
Well-Known Member
- Joined
- Feb 25, 2008
- Messages
- 5,589
All of the major ammo brands are publishing the same velocity for both cartridges because that is what they want you to believe, if you look back before the WSM came about, Winchester ammo was loaded to 3090fps with a 180gr bullet, it has since been downloaded to be no faster than the WSM, if this is not HYPE, I don't know what is.I have never shot the 300 WM but I have a WSM. With H4350 I can get 3050 with 168 TTSX's and 3020 fps with 180 gr E-Tips. With Fed factory loads I get about 3000 fps with 180 SP's and 180 AB's which is 40 fps faster than publihed. This is out of a Sako 85 Finnlight with 24"bbl.
Fed publishes the same velocity for the WM and WSM in the 180 gr bullets. From everything that I've read the 300 WSM is very close and sometimes equal to the WM. I like the shorter cases and especially like no belts.
To say that shape of case and efficiency has no effect on velocity is IMO delusional.
Why is it delusional to believe that, grain for grain, the difference in velocity is proportional, my understanding is that a reduction of powder of 10% will have a 2% reduction in velocity, which I have tested to be true about 90% of the time, exactly where the 300WSM lies against the 300WM cartridge, there is no substitute for more cubic inches or more case capacity, physics doesn't lie.
I agree that the WSM cases are efficient, but not in a manner that makes them burn less powder and magically get higher velocities than a case that burns more powder. Who can prove that the 300WM is less efficient than the 300WSM when compared against case expansion ratio's?
It just simply isn't true, and cannot be proved in the real world.
There used to be a thing called "overbore capacity", this doesn't cut it anymore with the very slow powders that we have on offer, with the exception of the 7mm RUM.
Food for thought.
MagnumManiac.
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