.308 Norma Magnum
| .308 Norma Magnum | ||||||||||||
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.308 Norma magnum cartridge.
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| Type | Rifle | |||||||||||
| Place of origin | Sweden | |||||||||||
| Production history | ||||||||||||
| Designer | Nils Kvale, Norma | |||||||||||
| Designed | 1960 | |||||||||||
| Manufacturer | Norma | |||||||||||
| Produced | 1960 to 1961 components only, 1961 to present as loaded ammunition | |||||||||||
| Specifications | ||||||||||||
| Parent case | .300 H&H Magnum | |||||||||||
| Case type | Rimless, Belted | |||||||||||
| Bullet diameter | .308 in (7.8 mm) | |||||||||||
| Neck diameter | .340 in (8.6 mm) | |||||||||||
| Shoulder diameter | .489 in (12.4 mm) | |||||||||||
| Base diameter | .512 in (13.0 mm) | |||||||||||
| Rim diameter | .530 in (13.5 mm) | |||||||||||
| Rim thickness | .048 in (1.2 mm) | |||||||||||
| Case length | 2.56 in (65 mm) | |||||||||||
| Overall length | 3.30 in (84 mm) | |||||||||||
| Primer type | large rifle magnum | |||||||||||
| Maximum pressure | 55,100 psi (380 MPa) | |||||||||||
| Ballistic performance | ||||||||||||
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| Source(s): http://www.norma.cc | ||||||||||||
The .308 Norma Magnum (7.62×65mmBR) cartridge was created by Nils Kvale at Norma, Sweden. Like the larger .358 Norma Magnum it is based on the .300 H&H Magnum. The length of the case is the longest that would fit in a standard Mauser action. While it appeared to have a bright future initially, it was soon superseded in popularity by the .300 Winchester Magnum. The first, and one of the few, manufacturers to offer rifles in .308 Norma Magnum was Schultz & Larsen of Denmark and they still are.
In the late 1940s Kvale designed a wildcat called 8mm Kvale. It was intended for use in the German surplus 8mm Mauser M98 that flooded the American market after the war and was therefore nicknamed 'Poor Man's Magnum'. Kvale used the case from the .300 H&H Magnum and reduced the rim diameter so it would fit the bolt of a Mauser M98. The lessons learned from this cartridge were put into the .308 and .358 Norma Magnum.
Cases for the cartridge can be purchased from Norma or made in three ways: Necking up a 7 mm Remington Magnum case, necking down a .338 Winchester Magnum case, or running .300 Winchester Magnum cases through a full-length sizing die. Since the first two options leave the brass a bit short, the third is generally considered to be the best option. Ammunition for this caliber is not cheap (typically US$50–60 for 20 cartridges) and as such it is mainly of interest only to handloaders who own a rifle chambered in this caliber. The cartridge makes use of a belted case for headspacing.
It's short powder column give it an edge in efficiency over most of the older.30 cal magnums, not including ultra magnums or wsm caliber. the longer neck helps with seating longer/ heavier projectiles better than the shorter necked 300 win mag. The shorter neck means tha the projectile in certain rifles has to go deeper into the case whereby taking up more powder space.
The demise of the Norma magnum case can be summed up as a marketing failure on Normas part. Although rifles were available in this caliber only brass for reloading was available in large quantities, with Norma the only manufacturer of ready made ammo. Winchester however was able to produce the popular model 70 rifles in their caliber and mass-produced ready made ammo to the American public. This was the main reason of the 300 Winchester magnums popularity over the 308 norma mag. The 308 norma magnum is considered by many reloaders as a better caliber compared to the 300 winchester magnum that essentially replaced it.
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Wikipedia