.300 Weatherby Magnum
The.300 Weatherby Magnum is a.30 caliber rifle cartridge created by Roy Weatherby in 1944 and produced by Weatherby. It has become the most popular of all the Weatherby cartridges.
.300 Weatherby Magnum

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- rifle cartridge.
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The.300 Weatherby Magnum is a.30 caliber rifle cartridge created by Roy Weatherby in 1944 and produced by Weatherby. It has become the most popular of all the Weatherby cartridges.
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original value insufficient · checked 25 September 2026
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Authority files
wikidata · Q4545248 · wikipedia · .300 Weatherby Magnum
In this article
Background
Background
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. The Weatherby was first introduced in 1944, and the.300 Winchester Magnum was introduced in 1963. In recent years, Remington, Winchester and Ruger have produced rifles in this caliber, and most major ammunition manufacturers now supply factory loads.
Performance
Performance
Historically, Weatherby claimed that this is the most powerful.30 caliber magnum rifle commercially available, but the recently introduced.300 Remington Ultra Magnum, the.300 Norma Magnum and Weatherby's own.30-378 Weatherby Magnum are now more powerful. Of course there are quite a few very large.30 caliber wildcat cartridges. When comparing the.300 RUM and the.300 Weatherby Magnum, however, there is a 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 pressures, and as a consequence, surpass the.300 Weatherby in power. The.300 Weatherby is commonly used by big-game hunters all over the world.
Use
Use
The SAS captured a rifle chambered in.300 Weatherby Magnum during the Falklands War.
Primary material
Documents and archives
authority record
- Wikidata, structured authority record Q4545248:.300 Weatherby Magnum
Unverified · Wikidata
reference work
- “.300 Weatherby Magnum”, English Wikipedia, consulted as further reading
Reputable secondary · Wikipedia
Notes from the source article
Cited by Wikipedia
Notes from the source article
These works are cited by the source article, in its own numbering. They are recorded as its citations, not as sources VALÉORINE has verified.
- 1..300 Weatherby Magnum page at Weatherby
- 2.Bullets, Speer. Speer Bullets Reloading Manual #14. Speer. 525. 2009. 978-0-9791860-0-4.
- 3.Bullets, Speer. Speer Bullets Reloading Manual #14. Speer. 540. 2009. 978-0-9791860-0-4.
- 4..300 Weatherby by Chuck Hawks (subscription required)
- 5.Imperial War Museums. Weatherby Mk 5, .300 Magnum. iwm.org.uk.
References
Citations
References
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Broader subject
1- rifle cartridgeTerminology
Established from a fact already recorded on a verified source.
The Encyclopedia exists whether or not anything is for sale. Corrections are recorded rather than overwritten, and every version of this record is kept. Published 14 August 2026.
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