7mm Remington Magnum

7mm Remington Magnum

7mm Remington Magnum Cartridge
Type Rifle
Place of origin  United States
Production history
Designer Remington Arms Company
Designed 1962
Manufacturer Remington
Produced 1962–Present
Specifications
Parent case .375 H&H Magnum
Bullet diameter .284 in (7.2 mm)
Neck diameter .315 in (8.0 mm)
Shoulder diameter .491 in (12.5 mm)
Base diameter .512 in (13.0 mm)
Rim diameter .532 in (13.5 mm)
Case length 2.5 in (64 mm)
Overall length 3.29 in (84 mm)
Rifling twist 1/9 to 1/10"
Primer type Large rifle magnum
Ballistic performance
Bullet weight/type Velocity Energy
110 gr (7 g) Barnes TTS 3,500 ft/s (1,100 m/s) 2,992 ft·lbf (4,057 J)
140 gr (9 g) Nosler AB 3,110 ft/s (950 m/s) 3,006 ft·lbf (4,076 J)
150 gr (10 g) Soft Point 3,110 ft/s (950 m/s) 3,221 ft·lbf (4,367 J)
165 gr (11 g) Sierra GK BT 2,950 ft/s (900 m/s) 3,188 ft·lbf (4,322 J)
175 gr (11 g) Soft Point 2,860 ft/s (870 m/s) 3,178 ft·lbf (4,309 J)
Test barrel length: 24"
Source(s): Accurate Powder [1]

The 7mm Remington Magnum rifle cartridge was introduced as a commercially available round in 1962,[2] along with the new Remington Model 700 bolt-action rifle. It is a member of the belted magnum family that is directly derived from the venerable .375 H&H Magnum.[3] The original purpose of the belted magnum concept taken from the .300 H&H and .375 H&H, was to provide precise control of the head-space, since the sloping shoulders, while easing cartridge extraction, provided poor head-spacing. Improved cartridge extraction reliability is desirable while hunting dangerous game, which would be of concern when needing a fast follow up shot. The 7mm Rem is based on the commercial Winchester .264 Win Mag, .338 Win Mag, and .458 Win Mag, which were based on the same belted .300 H&H and .375 H&H cases, trimmed to nearly the same length as the .270 Wby Mag.[3]

On its introduction, the 7mm Rem. Mag. substantially usurped the market share held by the .264 Winchester Magnum, which went into sharp decline in popularity and sales after 1962.[4] Maximum pressure is set by SAAMI at 61,000 PSI.[2] 52,000 CUP [5] Remington has recently offered Managed Recoil ammunition for achieving reduced recoil when shooting and for generating less meat damage when hunting smaller game.

Design

The 7mm Remington Magnum offers ballistics better than the .30-06 Springfield with bullet weights of 175 grains and less, one of the more popular loads being a 160 grain spitzer loaded to 3,000 ft/s (910 m/s). This is due both to the higher muzzle velocity of the magnum compared to the Springfield and that .284 diameter bullets tend to have better ballistic coefficients than .308 diameter bullets of comparable mass. It is arguable that the 7 mm Remington Magnum offers marginally better ballistics with 175 grain bullets, the heaviest bullet commonly used in the caliber. The .30-06 Springfield can, however, be loaded with heavier bullets up to 220 grains.

Use

Because of its flat shooting nature and the relatively tolerable recoil, the 7mm Remington Magnum is especially popular for Western plains use in the United States, as well as for use on plains game in Africa. It has also been chambered in sniper rifles as the US Secret Service counter-sniper team has deployed this cartridge in urban areas . Popular online gun author Chuck Hawks calls the 7mm Remington "one of the great all-around rifle cartridges."[6]

Some cartridges in 7mm Remington Magnum (circle size proportional to recoil).
Game Class vs 6 inch Maximum Point Blank Range. 
Sectional Density vs Ballistic Coefficient. 

Choice of bullet and barrel length

The choice of bullet made when reloading is critical, as the velocity of bullets at close ranges may result in a less tough bullet disintegrating without providing significant penetration on especially tough game. Thus one would do well to use a premium bullet of some sort, for instance a bonded bullet. The choice of barrel length is also critical, as a 26 or 27-inch (690 mm) barrel is commonly needed to achieve the full velocity potential of the cartridge, and a 24 inches (610 mm) barrel should be viewed as a practical minimum. This is because in shorter, i.e., sporter, barrels, of approximately 22 inches (560 mm), the cartridge ballistics deteriorate to much the same as those achieved in a .270 Winchester, while generating more recoil and muzzle blast than the .270.

See also

References

  1. ↑ 7 mm Remington Magnum data from Accurate Powder" Archived July 7, 2011, at the Wayback Machine.
  2. 1 2 Accurate (2000). Accurate Smokeless Powders Loading Guide (Number Two (Revised) ed.). Prescott, AZ: Wolfe Publishing. p. 247. Barcode 94794 00200.
  3. 1 2 Speer Reloading Manual
  4. ↑ .264 Win Mag data from Accurate Archived September 28, 2007, at the Wayback Machine.
  5. ↑ Speer Reloading Manual # 10 & Hornady Handbook of Cartridge Reloading 3rd Edition
  6. ↑ The 7mm Remington Magnum by Chuck Hawks

External links

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