8mm Rem Mag Load Data
January 03, 2011
For reloading the 8mm Rem Mag, there's an excellent selection of 8mm bullets (.323) is currently available: (from left) Barnes 180-gr. Triple Shock-X; Nosler 180-gr. Ballistic Tip; Hornady 195-gr. InterLock; Barnes 200-gr. Triple Shock-X; Nosler 200-gr. Partition; Nosler 200-gr. AccuBond; Speer 200-gr. Hot-Cor; Swift 220-gr. A-Frame; Sierra 220-gr. Spitzer Boat Tail; and Speer 170-gr. Semi-Spitzer.
Remington has a habit of bringing out neat cartridges just a bit off the bubble, and the 8mm Remington Magnum is certainly one of them. It was introduced in 1977 in the Model 700 BDL, but was not generally available until the following year. The chambering never sold well, however, and it was discontinued as a standard catalog item in 1999. In fact, only 20,470 8mm RMs were made, and the majority (15,295) were BDLs. Its last gasp was a limited run of 2,133 M700 Classics made in 1998 and a smattering of Custom Shop versions made between 1986 and 1996.
But the Big Green's belted Big 8 is a terrific big-game round, on par with the .300 and .340 Weatherbys, .300 and .338 Winchester Magnums, and Remington's current beltless .30- and .338-caliber Ultra Magnums.
Our test rifle is an original M700 made in 1978. Its previous owner has passed away, but his daughter graciously loaned it to us. She informed me that her father had taken this rifle to Africa and used it with great success. Its 24-inch barrel has a 1:10 twist, standard for the cartridge. The scope was a Burris Fullfield II 3-9x40 in vintage Redfield mounts.
The 8mm Rem Mag was derived from the full-length (2.850 inch) belted magnum case, with minimal body taper and a sharp, 25-degree shoulder. This provides plenty of room for propellant, and consequently, the round delivers impressive ballistics. Remington factory ammo previously offered 185- and 220-grain PSP Core-Lokt bullets. The current factory load consists of a 200-grain Swift A-Frame, cataloged at 2,900 fps (it registered 2,846 fps from our test rifle). These ballistics are easily duplicated with handloads.
We used a set of RCBS dies in a Redding T-7 Turret press for loading chores. Preparing ammunition for the 8mm Rem Mag presents no particular problem, but, as with any other belted case, one must pay attention to the sizing die setting with respect to headspace. Since factory ammo has to work in every properly chambered rifle, it headspaces on the belt. Firing moves the shoulder forward - sometimes a lot. Thus, when sizing the fired case, if the shoulder is set back too far, case-head separations often result after only a few loadings.
We highly recommend the use of a Wilson Adjustable Case Gauge to set the sizing die. Handloads will then have a crush fit on the shoulder and will not headspace on the belt. This prolongs case life considerably. Also, stick with loads that approach 100 percent load density for uniform ballistics.
Remington ads at the time of its introduction extolled the virtues of the 8mm Rem Mag, stating that the round had "high energy without developing excessively uncomfortable recoil." Those ad guys were obviously a lot tougher than I am. The M700 weighed almost nine pounds with scope, but recoil with full loads is over 30 ft-lbs, so I tested from a Caldwell Lead Sled with two 25-pound bags of shot as ballast. This made firing hundreds of test loads a breeze. All groups were fired at 100 yards, and accuracy with all bullets tested was eminently suitable for any big game. The barrel was scrubbed squeaky clean, dried and a fouling shot fired prior to testing each load combination.
Only the slowest powders, such as Reloder 25, Magnum, Retumbo, MagPro, H-1000 and similar numbers, are suitable for the 8mm Rem Mag. Bullet selection for the 8mm is surprisingly good, considering the few cartridges available in the caliber. From 180-grain spitzers to 220-grain bruisers, there is a perfect bullet for any game appropriate to the 8mm Rem Mag. All of the spitzer-type bullets have very high ballistic coefficients - they fly flat and hit hard.
The 8mm Rem Mag doesn't take a back seat to many cartridges when it comes to raw game-stopping power, and muzzle energies approaching 4,000 ft-lbs were achieved with most of our loads.
The M700's magazine length of 3.7 inches allows considerable flexibility in seating depth, and a little experimentation revealed that this particular rifle liked to give the bullets a running start to the rifling. Thus, all bullets were seated .030 inch off the lands, except for the Barnes Triple Shock-X and Swift A-Frames, which were loaded .050 inch off, as recommended by their makers.
Barnes TS-X bullets offer the hunter a no-lead alternative and provide deep penetration and controlled expansion. With the 180-grain version, a load of 85.0 grains of H-1000 produced a sizzling 3,025 fps and grouped 1.34 inches. The same charge weight of MagPro zipped this bullet along at 3,051 fps, and it still shot under two inches. In addition to MagPro, the 200-grain TS-X liked Reloder 25. With 84.0 grains, velocity was only one lone foot-pound shy of 3,000, and groups averaged 1.57 inches.
A "best of show" load was the Hornady 195-grain InterLock over 84.0 grains of Reloder 25. It consistently averaged under an inch at a sizzling 2,936 fps.
Nosler offers three 8mm bullets that excel in the 8mm Rem Mag. A terrific load with the 180-grain Ballistic Tip is with H-4831SC, which grouped under an inch at 2,979 fps. The 200-grain Nosler Partition was boosted along at 2,950 fps by 85.0 grains of H-1000. Also of note is the new 200-grain AccuBond over 85.0 grains of MagPro at 2,970 fps.
For what Jack O'Conner called a "Sunday go-to-meetin' load," check out the 220-grain bullets. Sierra's 220-grain SBT's thick jacket will stand up to the velocity, and it shot into an inch and a half with 83.0 grains of H-1000. The highest muzzle energy of any load was with the ultra-tough 220-grain Swift A-Frame. Pushed by 82.0 grains of Reloder 25 at 2,963 fps, it had muzzle energy of a crushing 4,290 ft-lb - enough for anything in North America.
A good moderate load is the Speer 170-grain Semi-Spitzer with 55.0 grains of H-4895 at a leisurely 2,597 fps. This mimics the 8x57 Mauser and makes a terrific low-recoil load for deer.
The 8mm Remington Magnum can hold its own anywhere. Unfortunately, it will probably continue its fade into obscurity. Nevertheless, the hunter armed with one is well prepared, especially with handloads created with today's high-tech bullets and ultra-slow powders.