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Range Report 300wm/300wsm

muleman

Sergeant
Full Member
Minuteman
Jan 8, 2010
205
0
71
Denton, Neb.
I just got the Hornaday 8th edition. Can anyone explain to me how they can get the same velosity 2800fps with 4gr. less powder (IMR4831) with the same 190gr. bullet, out of a 300 WSM?
 
Re: 300wm/300wsm

I wonder if the WSM is spec'd out as a higher pressure cartridge? Like Hodgdon lists the 7mm RM as being a lower pressure loading than a 300 WM. I would guess part of it is how high are you willing to run the pressure. I would say case design, but both being magnum type cases I am not sure it would make a lot of difference here.

Gary
 
Re: 300wm/300wsm

The 300WSM has more efficient case dimentions. It makes better use of the powder and doesn't need as much powder to run just as well. The problem is that it doesn't handle the big long bullets quite as well as the 300WM.

I had a really cool and informative page saved at one time that outlined and explained in depth what changing different aspects of a case does to it. For whatever reason i don't have it anywhere. Maybe another Hide member does and will be nice enough to post it.
 
Re: 300wm/300wsm

The WSM case is fat and short. The pressure created in that wider yet shorter area is very efficient, as opposed to a slightly thinner yet longer case.

You think thats a mystery?

Have a look at WSM vs RSAUM?

The Short action ultra mag cases are almost the same as the WSM cases, but shoulders are slightly different and yet the SAUM gets similar velocity numbers with significantly less powder than a WSM.

Keep in mind these cases are all relatively new and much more efficient than the old school belted winmag case.
 
Re: 300wm/300wsm

There is much speculation about the efficeincy of the 300 WSM over the 300 Win. I believe that any increased or equal velocity using the WSM with the same or slightly lower powder charge is a result of the shorter cartridge leaving more usable barrel for any length. The shorter case/chamber leaves more bore available to accelerate the bullet with any given length.
 
Re: 300wm/300wsm

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MikeSWammo</div><div class="ubbcode-body">There is much speculation about the efficeincy of the 300 WSM over the 300 Win. I believe that any increased or equal velocity using the WSM with the same or slightly lower powder charge is a result of the shorter cartridge leaving more usable barrel for any length. The shorter case/chamber leaves more bore available to accelerate the bullet with any given length.</div></div>

Shorter fatter powder columns provide increased efficiency.
 
Re: 300wm/300wsm

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: LordofPangea</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MikeSWammo</div><div class="ubbcode-body">There is much speculation about the efficeincy of the 300 WSM over the 300 Win. I believe that any increased or equal velocity using the WSM with the same or slightly lower powder charge is a result of the shorter cartridge leaving more usable barrel for any length. The shorter case/chamber leaves more bore available to accelerate the bullet with any given length.</div></div>

Shorter fatter powder columns provide increased efficiency. </div></div>

Yes, we are all familiar with this theory.

However, The contribution of the short/fat cartridge's efficiency is negligible when compared to the resulting longer effective barrel length (nearly 1/2 inch) and the higher pressures(62K+ for the Win, and 64K+ for the WSM) to which most factory short magnum ammunition is loaded.

I tend to believe that the more uniform burn of the short/fat cartridge lends more to accuracy than velocity.
 
Re: 300wm/300wsm

I tend to agree with MikeSWammo
smile.gif


The short fat powder column theory needs a lot of statistically meaningful testing (that I've never seen published) to prove the higher efficiency solely on it.
 
Re: 300wm/300wsm

Yes, we are all familiar with this theory.

However, The contribution of the short/fat cartridge's efficiency is negligible when compared to the resulting longer effective barrel length (nearly 1/2 inch) and the higher pressures(62K+ for the Win, and 64K+ for the WSM) to which most factory short magnum ammunition is loaded.

I tend to believe that the more uniform burn of the short/fat cartridge lends more to accuracy than velocity.
[/quote]

I tend to believe that a more efficient cartridge contributes more to the FPS goal than barrel length, I will admit that this is not scientifically established on my part and as you can see from these last few posts there is frequent use of the words "tend" and "believe".
 
Re: 300wm/300wsm

Its almost like we are talking about the tooth fairy! LOL

Weather or not we agree on where they come from, we can all agree that there are many advantages to the WSM case design. Velocity, efficeincy, and accuracy are all greater than any other cartridge of equal case capacity.
 
Re: 300wm/300wsm

my KMW 300 win mag was pushing 210 berger vld's at 3000fps, 24 moa to 1000yds, no pressure signs , even in 105deg weather

28" barrel krieger

no WSM ever did that!

lots of horsepower on target . . . yeah git it, git it