7mm Remington Magnum

Last updated
7mm Remington Magnum
.284 Winchester with .223 Rem and .308 Win.JPG
Left to right: .308 Winchester, .284 Winchester and 7mm Remington Magnum
Type Rifle
Place of origin United States
Production history
Designer Remington Arms Company
Designed1962
ManufacturerRemington
Produced1962–present
Specifications
Parent case .375 H&H Magnum
Case typeRimless, bottleneck
Bullet diameter.284 in (7.2 mm)
Land diameter.277 in (7.0 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 length2.5 in (64 mm)
Overall length3.29 in (84 mm)
Case capacity82.0  gr H2O (5.31 cm3)
Rifling twist1/9 in (230 mm) to 1/10 in (250 mm)
Primer typeLarge rifle magnum
Maximum pressure (C.I.P.)62,366 psi (430.00 MPa)
Maximum pressure (SAAMI)61,000 psi (420 MPa)
Maximum CUP52,000 CUP
Ballistic performance
Bullet mass/typeVelocityEnergy
110 gr (7 g) Barnes TTS[ citation needed ]3,500 ft/s (1,100 m/s)2,992 ft⋅lbf (4,057 J)
140 gr (9 g) Nosler AB[ citation needed ]3,110 ft/s (950 m/s)3,006 ft⋅lbf (4,076 J)
150 gr (10 g) Soft Point[ citation needed ]3,110 ft/s (950 m/s)3,221 ft⋅lbf (4,367 J)
165 gr (11 g) Sierra GK BT[ citation needed ]2,950 ft/s (900 m/s)3,188 ft⋅lbf (4,322 J)
175 gr (11 g) Soft Point[ citation needed ]2,860 ft/s (870 m/s)3,178 ft⋅lbf (4,309 J)
Test barrel length: 24 in (610 mm)
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 Magnum and .375 H&H Magnum, was to provide precise headspace control, since the sloping shoulders, while easing cartridge extraction, were unsuitable for this purpose. Improved cartridge extraction reliability is desirable while hunting dangerous game, in particular when a fast follow-up shot is required. The 7mm Remington Magnum is based on the commercial .264 Winchester Magnum, .338 Winchester Magnum, and .458 Winchester Magnum, which were based on the same belted .300 H&H Magnum and .375 H&H Magnum cases, trimmed to nearly the same length as the .270 Weatherby Magnum. [3]

Contents

History

On its introduction, the 7mm Remington Magnum substantially usurped the market share held by the .264 Winchester Magnum, which went into sharp decline in popularity and sales after 1962. [4] By 1963 Winchester introduced the .300 Winchester Magnum to compete with Remington's new belted magnum cartridge. Both cartridges have remained the most popular magnum calibers among hunters and shooters ever since.

Les Bowman, hunting editor and outfitter was primarily responsible for the development and introduction of the cartridge. He noticed the need for a lower recoil cartridge capable of taking elk-sized game at the longer ranges common where he guided clients. He found that the .300 Weatherby Magnum produced too much recoil for many hunters, resulting in poor shot placement, and the .270 Winchester combined with the bullets available at the time, lacked the downrange energy to cleanly kill game. He found in the .275 Holland & Holland Magnum, a suitable alternative, but unavailable in the US. [5]

Design

The 7mm Remington Magnum offers ballistics better than the .30-06 Springfield with all available bullet weights, 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. Because of the smaller bullet diameter .284 diameter bullets also have higher sectional density than .308 diameter bullets, and because of that better penetration in the target (it takes a 206-grain .308 diameter bullet to get the same sectional density as a 175-grain .284 bullet, an increased weight that requires 15-20% more muzzle energy to get the same muzzle velocity). The heaviest commercially loaded ammo available for the 7mm is 195 grains, [6] while the .30-06 Springfield can be loaded with bullets up to 220 grains, but for a .308 caliber to equal the flat trajectory and penetration of a .284 diameter 180-grain bullet with a muzzle velocity of 2,860 ft/sec (870 m/s), as offered for the 7mm Remington Magnum, requires muzzle energy close to what the .300 Winchester Magnum can offer, i.e. well beyond what the .30-06 can deliver.

Cartridge dimensions

The 7mm Remington Magnum has 5.31 ml (82-grain) H2O cartridge case capacity.

7 mm Remington Magnum.png

7mm Remington Magnum maximum C.I.P. cartridge dimensions. All sizes in millimeters (mm). [7]

Americans would define the shoulder angle at alpha/2 = 25 degrees. The common rifling twist rate for this cartridge is 241 mm (1 in 9.49 in), 6 grooves, Ø lands = 7.04 mm, Ø grooves = 7.21 mm, land width = 2.79 mm. The cartridge uses a large rifle magnum primer type.

According to the official C.I.P. (Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives) rulings, the 7mm Remington Magnum case can handle up to 430.00 MPa (62,366 psi) Pmax piezo pressure. In C.I.P. regulated countries every rifle cartridge combo has to be proofed at 125% of this maximum C.I.P. pressure to certify for sale to consumers. This means that as of 2016, 7mm Remington Magnum chambered arms in C.I.P. regulated countries are proof tested at 537.50 MPa (77,958 psi) PE piezo pressure. [7]

The SAAMI maximum average pressure (MAP) for this cartridge is 61,000 psi (420.58 MPa) piezo pressure. [8]

Use

7mm Remington.jpg

The 7mm Remington Magnum is a big game hunting cartridge capable of taking thin skinned game at considerable hunting ranges. Due to its high ballistic coefficient, which is common in all .284" caliber cartridges, the 7mm Rem Mag bucks wind efficiently. Because of its flat shooting nature and the relatively tolerable recoil, the 7mm Remington Magnum is especially popular for big-game hunting in Western Canada and in the United States, for plains game in Africa, and mountain hunting around the world. It has also been chambered in sniper rifles as the US Secret Service counter-sniper team has deployed this cartridge in urban areas along with the .300 Winchester Magnum. [9] Popular online gun author Chuck Hawks calls the 7mm Remington "one of the great all-around rifle cartridges." [10]

Alternative cartridges

The 7mm Winchester Short Magnum cartridge, a rebated rim bottlenecked centerfire short magnum introduced in 2001, is probably the closest ballistic twin of the 7mm Remington Magnum. The 7mm Winchester Short Magnum is considerably shorter and fatter and has a steeper shoulder angle and a shorter neck (6.17 mm) than the 7mm Remington Magnum. This makes the 7mm Remington Magnum case with its 6.89 mm long neck better suited for loading long, heavier bullets. On the other hand, the proportions of 7mm Winchester Short Magnum promote good internal ballistic efficiency that allows the 7mm Winchester Short Magnum to fire shorter lighter bullets at slightly higher muzzle velocities while using less propellant than the classically proportioned 7mm Remington Magnum.

The commercially rarer 7mm Remington Short Action Ultra Magnum cartridge, a rebated rim bottlenecked centerfire short magnum introduced in 2002, is probably the other closest ballistic twin of the 7mm Remington Magnum. The 7mm Remington Short Action Ultra Magnum is considerably shorter and fatter and has a steeper shoulder angle and a longer neck (7.90 mm) than the 7mm Remington Magnum. This makes the 7mm Remington Short Action Ultra Magnum better suited for loading long heavier bullets.

These 21st-century ballistic twin short fat magnum cartridges can handle 440.00 MPa (63,817 psi) Pmax piezo pressure according to the C.I.P. or a maximum average pressure of 65,000 psi (448.16 MPa) piezo pressure according to the SAAMI.

The 7mm Precision Rifle Cartridge (7mm PRC) [11] was introduced in 2022 and is essentially a necked-down shortened version of the .375 Ruger. The 7mm PRC cartridge case capacity is 5.05 ml (78 grains) H2O. The .375 Ruger cartridge case was used by Hornady as the basis for new long-range cartridges, since it had the capability to operate with high chamber pressures (65,000 psi (448.16 MPa) Pmax piezo pressure according to the SAAMI), which combined with a neck and barrel throat optimized for loading relatively long and heavy very-low-drag bullets without the need to seat the bullets deeply recessed into the case result in adequate muzzle velocities from bolt-action rifles. Rifles chambered for the 7mm PRC provide slightly improved ballistics over the 7mm Remington Magnum and must be capable of handling (long-action length) 3.34 in (84.84 mm) overall length cartridges. [12] [13]

Another alternative cartridge that provides slightly improved ballistics over the .7mm Rem Mag, is the 7mm Weatherby Magnum, which though released to the market 18 years before, never reached the popularity of the former, mainly because of Weatherby rifles' high price and since the barrels for Weatherby's cartrdige initially had a 1:12 twist, being too slow to stabilize heavier bullets.

Choice of bullet and barrel length

Bullet choice when reloading is critical, as bullet velocity at close ranges may result in less robust bullets disintegrating without providing significant penetration on especially tough game. [14] Thus one would do well to use a premium bullet of some sort, for instance a bonded bullet. [15] The choice of barrel length is also critical, as a 26-or-27-inch (660 or 686 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 (559 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 Winchester.

See also

Related Research Articles

<span class="mw-page-title-main">.357 SIG</span> Pistol cartridge designed by SIG Sauer and Federal Premium Ammunition

The .357 SIG is a bottlenecked rimless centerfire handgun cartridge developed by the Swiss-German firearms manufacturer SIG Sauer, in cooperation with ammunition manufacturer Federal Premium. The cartridge is used by a number of law enforcement agencies.

<span class="mw-page-title-main">.357 Magnum</span> Revolver cartridge

The .357 Smith & Wesson Magnum, .357 S&W Magnum, .357 Magnum, or 9×33mmR is a smokeless powder cartridge with a 0.357 in (9.07 mm) bullet diameter. It was created by Elmer Keith, Phillip B. Sharpe, and Douglas B. Wesson of firearm manufacturers Smith & Wesson and Winchester. The .357 Magnum cartridge is notable for its highly effective terminal ballistics.

<span class="mw-page-title-main">.338 Lapua Magnum</span> Finnish rifle cartridge

The .338 Lapua Magnum is a Finnish rimless, bottlenecked, centerfire rifle cartridge. It was developed during the 1980s as a high-powered, long-range cartridge for military snipers. Due to its use in the War in Afghanistan and the Iraq War, the cartridge has become widely available.

<span class="mw-page-title-main">.308 Winchester</span> Rimless, centerfire, bottlenecked rifle cartridge

The .308 Winchester is a smokeless powder rimless bottlenecked rifle cartridge widely used for hunting, target shooting, police, military, and personal protection applications globally. It is similar, but not identical, to the 7.62×51mm NATO cartridge.

<span class="mw-page-title-main">7mm-08 Remington</span> Necked down .308Win

The 7mm-08 Remington is a rifle cartridge that is almost a direct copy of a wildcat cartridge developed around 1958 known as the 7mm/308. As these names would suggest, it is the .308 Winchester case necked down to accept 7 mm (.284) bullets with a small increase in case length. Of cartridges based upon the .308, it is the second most popular behind only the .243 Winchester. However, the .308 is more popular than both. In 1980, the Remington Arms company popularized the cartridge by applying its own name and offering it as a chambering for their Model 788 and Model 700 rifles, along with a limited-run series within their Model 7600 pump-action rifles during the early 2000s.

<span class="mw-page-title-main">.257 Weatherby Magnum</span> Rifle cartridge

The .257 Weatherby Magnum is a .257 caliber (6.53 mm) belted bottlenecked cartridge. It is one of the original standard length magnums developed by shortening the .375 H&H Magnum case to approx. 2.5 in (64 mm). Of the cartridges developed by Roy Weatherby, the .257 Weatherby Magnum was known to have been his favorite, and the cartridge currently ranks third in Weatherby cartridge sales, after the .30-378 Weatherby Magnum and the .300 Weatherby Magnum.

<span class="mw-page-title-main">.375 H&H Magnum</span> British rifle cartridge

The .375 H&H Magnum, also known as .375 Holland & Holland Magnum, is a medium-bore rifle cartridge introduced in 1912 by London based gunmaker Holland & Holland. The .375 H&H cartridge featured a belt to ensure the correct headspace, which otherwise might be unreliable, given the narrow shoulder of the cartridge case. The cartridge was designed to use cordite which was made in long strands – hence the tapered shape of the case, which, as a beneficial side effect also helped in smooth chambering and extraction from a rifle's breech.

<span class="mw-page-title-main">.300 Winchester Magnum</span> Rifle cartridge

The .300 Winchester Magnum is a belted, bottlenecked magnum rifle cartridge that was introduced by the Winchester Repeating Arms Company in 1963. The .300 Winchester Magnum is a magnum cartridge designed to fit in a standard rifle action. It is based on the .375 H&H Magnum, which has been blown out, shortened, and necked down to accept a .30 caliber (7.62 mm) bullet.

<span class="mw-page-title-main">.338 Winchester Magnum</span> Rifle cartridge

The .338 Winchester Magnum is a .338 in (8.6 mm) caliber, belted, rimless, bottlenecked cartridge introduced in 1958 by Winchester Repeating Arms. It is based on the blown-out, shortened .375 H&H Magnum. The .338 in (8.6 mm) is the caliber at which medium-bore cartridges are considered to begin. The .338 Winchester Magnum is the first choice among professional brown bear guides in Alaska to back up clients where a powerful stopping caliber is required on charging bears. It is also the most popular medium-bore cartridge in North America and has the most widely available choice in rifles among medium bore rifles. The action length is the same as a .30-06, and most major rifle manufacturers in the United States chamber rifles for the cartridge including the semi-automatic Browning BAR Mk II Safari, making it a very powerful combination against charging dangerous game. The cartridge was intended for larger North American big-game species and has found use as for the hunting of thin-skinned African plains-game species.

<span class="mw-page-title-main">8mm Remington Magnum</span> Rifle cartridge

The 8mm Remington Magnum belted rifle cartridge was introduced by Remington Arms Company in 1978 as a new chambering for the model 700 BDL rifle. The 8mm Remington Magnum's parent case is the .375 H&H Magnum. It is a very long and powerful cartridge that cannot be used in standard length actions, such as those that accommodate the .30-06 Springfield.

<span class="mw-page-title-main">8×68mm S</span>

The 8×68mm S rebated rim bottlenecked centerfire rifle cartridge was developed in the 1930s by August Schüler of the August Schüler Waffenfabrik, Suhl, Germany as a magnum hunting cartridge that would just fit and function in standard-sized Mauser 98 bolt-action rifles. The bore has the same lands and grooves diameters as the German 7.92×57mm Mauser service cartridge. This is one of the early examples where a completely new rifle cartridge was developed by a gunsmith to fit a specific popular and widespread type of rifle.

The .264 Winchester Magnum is a belted, bottlenecked rifle cartridge. Except for the .244 H&H Magnum and .257 Weatherby Magnum, it is the smallest caliber factory cartridge derived from the 2.85 in (72 mm) Holland & Holland belted magnum case. It was introduced in the late 1950s and early 1960s with the .338 Winchester Magnum and the .458 Winchester Magnum as one of a family of short-cased 2.5 in (64 mm) belted magnum cartridges developed by Winchester based on the .375 Holland & Holland parent case. It was officially introduced to the public by Winchester in 1959. After many years of dwindling use it began enjoying a mild resurgence in popularity in the mid-2000s among long range rifle enthusiasts and reloaders due to the high ballistic coefficient of the heavier 6.5mm bullets and increasing popularity of cartridges such as 6.5mm Creedmoor, .260 Remington, 6.5 Grendel, benchrest and wildcat cartridges in 6.5mm.

The .260 Remington cartridge was introduced by Remington in 1997. Many wildcat cartridges based on the .308 Winchester case had existed for years before Remington standardized this round.

The .300 Lapua Magnum (7.62×70mm) is a rimless, bottlenecked, centerfire cartridge developed for long-range rifles. The parent case of the .300 Lapua Magnum is the .338 Lapua Magnum necked down to a smaller caliber. The .338 cartridge case was selected to withstand high chamber pressures. Combining these high pressures with smaller, lighter bullets than its parent case, .300 Lapua Magnum loadings have high muzzle velocities.

<span class="mw-page-title-main">.416 Remington Magnum</span> Rifle cartridge

The .416 Remington Magnum is a .416 caliber (10.57 mm) cartridge of belted bottlenecked design. The cartridge was intended as a dangerous game hunting cartridge and released to the public in 1989. The cartridge uses the case of the 8 mm Remington Magnum as a parent cartridge. When the cartridge was released in 1988, author Frank C. Barnes considered the .416 Remington Magnum to be the "most outstanding factory cartridge introduced in decades".

The .375 Ruger (9.5×65.5mm) is a rimless, standard-length rifle cartridge designed for hunting large, dangerous game. It is designed to provide an increase in performance over the .375 H&H cartridge within the context of a standard-length rifle action. The cartridge was designed in partnership by Hornady and Ruger. In 2007, it was released commercially and chambered in the Ruger Hawkeye African and the Ruger Hawkeye Alaskan rifles.

<span class="mw-page-title-main">.325 Winchester Short Magnum</span> Rifle cartridge

The .325 Winchester Short Magnum, commonly known as the 325 WSM, is an 8mm caliber rebated rim bottlenecked centerfire short magnum medium bore cartridge. The cartridge was introduced by Winchester Ammunition in 2005.

<span class="mw-page-title-main">.284 Winchester</span> US rifle cartridge

The .284 Winchester (7.21x55mmRB) is a rebated rim firearm cartridge, introduced by Winchester in 1963.

<span class="mw-page-title-main">6.5mm Creedmoor</span> Centerfire rifle cartridge

The 6.5mm Creedmoor (6.5×48mm), designated 6.5 Creedmoor by SAAMI, 6,5 Creedmoor by the C.I.P. or 6.5 CM or 6.5 CRDMR for short, is a centerfire rifle cartridge introduced by Hornady in 2007. It was developed by Hornady senior ballistics scientist Dave Emary in partnership with Dennis DeMille, the vice-president of product development at Creedmoor Sports, hence the name. The cartridge is a necked-down modification of the .30 Thompson Center.

The .450 Rigby is a rifle cartridge designed in 1994 by John Rigby & Co. for the hunting of large, thick-skinned dangerous game animals in Africa. The cartridge is based on the .416 Rigby necked up to accept a .458 in (11.6 mm) bullet and is intended for use in magazine rifles. The cartridge should not be confused with .450 Nitro Express which was introduced by Rigby in 1898, and is a rimmed cartridge intended for use in double rifles.

References

  1. 7 mm Remington Magnum data from Accurate Powder"
  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. "Remington's Big Seven". www.americanrifleman.org. May 29, 2012.
  6. McAdams, John (2018-11-13). "7mm Rem Mag vs 300 Win Mag: What You Know May Be Wrong". Big Game Hunting Blog. Retrieved 2024-01-28.
  7. 1 2 C.I.P. TDCC sheet 7 mm Rem. Mag.
  8. ANSI/SAAMI Velocity & Pressure Data: Centerfire Rifle Archived 2013-07-02 at the Wayback Machine
  9. "7mm Remington Magnum" (PDF). Sierra Reloading Manual. Retrieved 31 August 2017.
  10. The 7mm Remington Magnum by Chuck Hawks
  11. "New Cartridge & Chamber 7mm Precision Rifle Cartridge (7mm PRC)" (PDF). saami.org. July 6, 2022. Retrieved 2023-07-13.
  12. Harmer, Jim (2023-07-17). "7mm PRC: Complete ballistic data (recoil, trajectory, energy)". Backfire. Retrieved 2023-07-17.
  13. Harmer, Jim (2022-11-21). "6.5 PRC vs 7 PRC vs 300 PRC: A ballistics comparison (plus hands-on experience)". Backfire. Retrieved 2023-07-17.
  14. Fackler, Martin L., "Wounding Patterns of Military Rifle Bullets", International Defense Review, 1989, pp. 59-64
  15. von Benedikt, Joseph. "Bullet Basics: Bonded vs. Non-Bonded Bullets". RifleShooter. Retrieved 31 August 2017.