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 this month 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-inch twist, standard for the cartridge. The scope is a Burris Fullfield II 3-9x40 in vintage Redfield mounts.
The 8mm RM was derived from the full-length (2.850 inch) belted magnum case, with minimal body taper and a sharp, 25-degree shoulder. That 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 8mm Rem. Mag. 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 RM 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 RM, 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. That 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 RM. 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 RM. All of the spitzer-type bullets have very high ballistic coefficients--they fly flat and hit hard.