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|.300 Weatherby Magnum|
.300 Weatherby cartridge
|Place of origin||USA|
|Parent case||.300 H&H Magnum|
|Case type||Belted, bottleneck|
|Bullet diameter||.308 in (Script error mm)|
|Neck diameter||.336 in (Script error mm)|
|Shoulder diameter||.492 in (Script error mm)|
|Base diameter||.512 in (Script error mm)|
|Rim diameter||.531 in (Script error mm)|
|Case length||2.825 in (Script error mm)|
|Overall length||3.562 in (Script error mm)|
|Primer type||Large rifle magnum|
|Maximum pressure||65,000 psi (Script error MPa)|
|150 gr (Script error g) SP||3,540 ft/s (Script error m/s)||4,173 ft·lbf (Script error J)|
|165 gr (Script error g) SP||3,390 ft/s (Script error m/s)||4,210 ft·lbf (Script error J)|
|180 gr (Script error g) BST||3,250 ft/s (Script error m/s)||4,223 ft·lbf (Script error J)|
|200 gr (Script error g) Partition||3,060 ft/s (Script error m/s)||4,158 ft·lbf (Script error J)|
|220 gr (Script error g) Rn-Ex||2,845 ft/s (Script error m/s)||3,954 ft·lbf (Script error J)|
| Test barrel length: 26|
Source(s): Weatherby 
Roy Weatherby already had experience with other custom cartridges such as his own .270 Weatherby Magnum when he created the .300 Weatherby. Like most of his other magnum cartridges, this is based on a blown-out .300 H&H Magnum case, using the signature Weatherby double-radius shoulder.
Historically, Weatherby claimed that this is the most powerful .30 caliber magnum rifle commercially available, but the recently introduced .300 RUM and Weatherby's own .30/378 Magnum are now more powerful. Of course there are quite a few very large .30 caliber wildcat cartridges.
One must note however when comparing the .300 RUM and the .300 Weatherby Magnum the difference in factory loadings. Performance data is often listed on the side of the ammunition box for those who wish to do an in-store comparison. On average, Weatherby factory ammo is loaded to higher chamber pressures than Remington or Winchester magnum rounds. The Remington round can be handloaded to equal or even surpass the .300 Weatherby in power.
- ↑ 1.0 1.1 .300 Weatherby Magnum page at Weatherby
- ↑ .300 Weatherby by Chuck Hawks (subscription required)(subscription required)
- .300 Weatherby Magnum at Accurate Powder Cartridge dimensions.
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