300wm and 338wm

What Speer says about the 340 Wby, and 250gr Barnes load data -

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What Speer says about the 340 Wby, and 250gr Barnes load data -

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There is something very wrong with that. A 14% increase in case capacity should net more than a 4% increase in velocity. Douglas mentions multiple 340s that push 250gr pills at 3100fps and I see no reason not to believe him.
 
There is something very wrong with that. A 14% increase in case capacity should net more than a 4% increase in velocity. Douglas mentions multiple 340s that push 250gr pills at 3100fps and I see no reason not to believe him.

Case capacity increase to velocity increase ratio is roughly a 4:1 ratio. John Barness has shown and proven that "rule" numerous times.
 
Maybe so, but 5000 ft/lb at the muzzle is easy for a .340 Wby... you are doing good to get 4000 ft/lb with the .338 WM... that is a sizeable step up, IMO.
 
Anybody who doesn't see something wrong with that data should get his eyes checked..........a 210 gn @ over 3200 fps but then the same rifle and cartridge loses 500 fps with a bump of 40 grns of bullet weight........less than 20% increase..........If you look at 358 NM you find a 200 fps difference from 200-250 gn bullets, if you look at the 338 WM with the same bullet weights the difference is 200 fps............I'm afraid I have to call BS...........Regardless of what you may believe there is a lot of discrimination against the Weatherby cartridge line up in reloading manuals..........I see it all the time. I saw a manual that gave the 308 NM a 30 fps advantage over a 300 Wby with 180 gn bullets, now really?????????????????

I just checked my latest testing of the 340 with 225 gn Nosler ABs..........3247 fps 4 shot avg, ES 24 fps....... 26" barreled Mod 70 Supergrade rechambered from 338. I also have test loads made up for it with Matrix 240 gn SRBT but have yet to test. Best guess is I'll end up between 3150 and 3200 fps because of the relatively short bearing surface due to the long ogive and the boat tail.
 
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From an article (written by Bob Hagel) on the 340 Wby in Big Bore Rifles & Cartridges. The test rifle is a Mark V. He mentions improved speeds using Norma brass which is harder than the original brass back in the day. Muzzle speeds with his handloads using 250gr bullets are ~2900 fps.

Note that 250gr factory ammo chronographed at 2860 fps.

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From an article (written by Bob Hagel) on the 340 Wby in Big Bore Rifles & Cartridges. The test rifle is a Mark V. He mentions improved speeds using Norma brass which is harder than the original brass back in the day. Muzzle speeds with his handloads using 250gr bullets are ~2900 fps.

Note that 250gr factory ammo chronographed at 2860 fps.

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"Chambered without freebore". 23.5" barrel.

So as Douglas said, it is an underperformer if your chamber doesn't have the proper freebore as dictated by Weatherby.
 
Hagels book (which I have) is from the 60s and he did not have the powders available to us now. Almost every magnum cartridge that was around then can be bettered by 100-200 fps with the newer slower powders we have today. However his book is a real delight to read and he uses the same criteria for loading that I do.....as long as it will hold primers for 3 or 4 rounds it is a good safe load, I happen to concur wholeheartedly...........
 
From Hagel's article on the 338 WM in Big Bore Rifles & Cartridges. Results with his 338 WM Ruger M77, same rifle as mine. Nice to have this data as I get into developing handloads for my 338 WM. Note the muzzle speed variation for different 250gr bullets.

Also note that with 250gr bullets, 338 WM muzzle speeds are only about 100 fps less than for his Mark V 340 Wby. ;)

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