Remington's Model 700 XCR II Part 2

A magnum cartridge is one that has greater powder capacity than a corresponding standard cartridge. Theoretically, since “magnum” is a relative term, there can’t be a magnum unless there is first a standard, but sometimes that rule is not followed. When the 338 Winchester Magnum was announced in 1958, there was no standard 338 caliber cartridge. However, the 338 Winchester Magnum is based on the belted 375 H&H Magnum, so we can chalk the label up to an inheritance. The 338 Remington Ultra Mag is larger in capacity than the 338 Winchester Magnum, so it truly earns its magnum moniker. However, as a magnum’s magnum, further identification was required to distinguish it from more run of the mill magnums. Leading with “Ultra” was, perhaps, a little ambitious, but it is a lot better than some of the alternatives: “Bigger Mag”, “Plus Size Mag”  or Mo’ Magnum.

What the heck does one do with a magnum, other than use it to develop a flinch and fuel wisecracks from old times who think the pinnacle of cartridge design was the 50-140 Sharps? In relative terms, magnums can make light bullets go very fast and very heavy bullets, pretty fast. Prairie grass and prong horns as far as the eyes can see or sheep jumping from summit to summit? Light bullet, high speed. Big, big bear that can get close enough for you to count his cavities and notice it had garlic caribou for breakfast? Heavy, heavy bullet and moderate velocity. The 338 Ultra Mag can do either, but there is a law of diminishing returns when it comes to bullet weights.

We’ve previously published handload data for the 338 Remington Ultra Mag, but we thought it would be useful to add the 300 grain Nosler AccuBond. This is not an endorsement or an indictment of this heavyweight, just observation.

Nosler, snosler…

Pictured right, left to right: 180 Grain Nosler AccuBond, 275 Grain Swift A-Frame and 300 grain Nosler AccuBond. The 300 grain AccuBond is long, 1.748″ to be precise, which means the bullet taxes some production rifle twist rates; calculations suggest a 1:9.8″ twist as a minimum. Weatherby’s 338-378 WM rifles have a 1:10″ twist,  Winchester’s 338 Winchester Magnums have a 1:10″ twist, but Remington’s 338 Ultra Mag has a 1:9.25″ twist. Remington, in its wisdom, thought that big case magnums probably should be planned to accommodate heavy bullets.

The Nosler AccuBond is listed by Nosler as suitable for use on deer, Elk, Bear, Moose, and African Game… depending on caliber. Not exactly a lot of insight into applications as they do not stipulate which calibers work with what game and “African Game” can mean anything from a mercat to an elephant.  Based on previous bullet testing, penetration and exterior ballistics, I’ll put myself out there and suggest the AccuBond in toughness and control of expansion falls between the Ballistic Tip for thin skinned game and the Partition that would drop a cape buffalo. With a tough 250 grain Nosler Partition and a tough 275 grain Swift A-Frame already available, what does the bonded 300 grain AccuBond have to offer?

Rocky Marciano or Primo Carnera?

Classic performance assessment using kinetic energy as an indication of power suggests that the 250 grain bullet is far superior to the 300 grain bullet and that there is not enough powder capacity in the 338 RUM to drive the Nosler fast enough to make it’s use advantageous. But there are lots of viable measurements of bullet effectiveness that would contradict a kinetic energy conclusion. Using Taylor KO Factor, the Sierra 250 grain rates a 37, while the Nosler 300 grain rates a 38. But then a regulation hardball thrown at only 45 MPH has a calculated KO factor of 58… so maybe we can set that assessment aside.

Momentum is a good indicator, at least for penetration potential. The 250 grain Sierra produces 3.4 pound-seconds of momentum, while the 300 grain Nosler produces 3.5 pound-seconds. At 200 yards the 250 Grain Sierra has dropped to 3.0 pounds-seconds of momentum, while the 300 Grain Nosler is still holding onto 3.19 pound-seconds of momentum. Stretching out to 400 yards the Sierra bullet is pulling along 2.7 pound-seconds and the Nosler bullet is still pegging 2.9.

Miscellaneous issues? The 300 grain bullet has greater mass than the 250. When a bullet impacts and begins to deform against a tapered wall jacket, theoretically, the longer the bullet, the more material to deform and the larger the mushroomed bullet. Larger wound cavity, the faster the bleed out. In terms of recoil the 250 grain generates 56 Ft-Lbs of recoil, 58 for the 300 grain Nosler. The Sierra bullet cost is 48¢ per, the Nosler 88¢ or $9.60 and $17.60, respectively, per box of 20.

Don’t let the facts get in the way of a good decision…

The best bullet depends on which church you attend as there is a lot of room for interpretation. Most of us spend a lot of time trying to make what we like subjectively fit into a scientific framework. There are way too many variables to control for any real analysis. The good news is that animals can be killed with a pointed stick or rock so there is a lot of latitude for success within any selection. I tend to stay with the rock ’em, sock ’em and shock ’em school of thought and favor the zippy 250 grain Sierra, probably because of the extended point blank range and Accurate, flat shooting and good terminal ballistics for my applications. For tough, closer in shooting, I like the jackets on Partitions and A-Frames, but that’s just me.

Warning: Bullet selections are specific, and loads are not valid with substitutions of different bullets of the same weight. Variations in bullet length will alter net case capacity,  pressure and velocity. Primer selection is specific and primer types are not interchangeable. These are maximum loads in my firearms and may easily be excessive in others. All loads should be reduced by 5%,  and developed following safe handloading practices as represented in established reloading manuals produced by component manufacturers. Presentation of these loads does not constitute a solicitation for their use, nor a recommendation.   Cartridge: 338 Remington Ultra Mag   Firearm: Remington Model 700 XCR II   Max COL: 3.600″   Bullet Diameter: 0.338″   Primer: CCI 250   Barrel: 26″   Reloading Dies: RCBS   Max case length: 2.760″   Group: Distance 100 yards – Three shots

COL and Capacity   Load Data & Performance Bullet Type Bullet Weight C.O.L. Inches Case Grains Water   Powder Charge Grains Muzzle Velocity FPS Muzzle Energy Ft/Lbs Group Inches Nosler AccuBond SPBT 180 3.535 99.7   MagPro 101.0 3306 4368 1.2 Nosler AccuBond SPBT 180 3.535 99.7   Re19 93.5 3302 4357 0.9 Nosler AccuBond SPBT 180 3.535 99.7   IMR7828SSC 97.0 3340 4459 1.1 Nosler AccuBond SPBT 180 3.535 99.7   Win780 96.5 3241 4199 1.4 Speer Hot-Cor SPFB 200 3.500 101.4   MagPro 101.0 3255 4705 1.2 Speer Hot-Cor SPFB 200 3.500 101.4   Re22 97.0 3251 4694 0.9 Speer Hot-Cor SPFB 200 3.500 101.4   IMR7828 97.0 3277 4768 1.0 Speer Hot-Cor SPFB 200 3.500 101.4   RS Magnum 103.0 3192 4524 1.3 Sierra GameKing SPBT 215 3.580 100.4   MagPro 100.0 3201 4892 0.9 Sierra GameKing SPBT 215 3.580 100.4   Re22 95.0 3171 4800 0.7 Sierra GameKing SPBT 215 3.580 100.4   IMR7828SSC 94.5 3129 4673 0.5 Sierra GameKing SPBT 215 3.580 100.4   RS Magnum 102.0 3183 4836 1.2 Speer Hot-Cor SPBT 225 3.600 100.6   MagPro 98.0 3094 4783 1.1 Speer Hot-Cor SPBT 225 3.600 100.6   IMR4831 92.0 3019 4553 1.3 Speer Hot-Cor SPBT 225 3.600 100.6   RS Magnum 101.0 3105 4816 1.1 Speer Hot-Cor SPBT 225 3.600 100.6   Viht N560 94.0 3116 4849 0.6 Hornady SST InterLock 225 3.590 96.7   MagPro 96.0 3109 4829 1.2 Hornady SST InterLock 225 3.590 96.7   Re22 91.0 3090 4769 0.9 Hornady SST InterLock 225 3.590 96.7   H4831SC 90.0 3007 4517 1.1 Hornady SST InterLock 225 3.590 96.7   Viht N560 92.0 3103 4811 0.8 Sierra GameKing 250 3.580 96.3   MagPro 95.5 3089 5298 1.0 Sierra GameKing 250 3.580 96.3   Re22 91.0 3042 5138 0.8 Sierra GameKing 250 3.580 96.3   Viht N560 92.0 3112 5377 1.0 Speer Grand Slam 250 3.555 97.8   MagPro 94.0 2966 4884 1.3 Speer Grand Slam 250 3.555 97.8   Re25 93.0 2950 4831 0.8 Speer Grand Slam 250 3.555 97.8   IMR7828SSC 90.0 2948 4824 1.0 Speer Grand Slam 250 3.555 97.8   RS Magnum 97.0 2974 4909 0.8 Woodleigh Weldcore PP 250 3.570 99.0   MagPro 95.0 2957 4854 1.1 Woodleigh Weldcore PP 250 3.570 99.0   Re25 94.0 2941 4801 1.2 Woodleigh Weldcore PP 250 3.570 99.0   IMR7828SSC 90.5 2971 4900 0.6 Woodleigh Weldcore PP 250 3.570 99.0   Viht N560 91.5 2998 4988 1.2 Swift A Frame 275 3.520 94.5   Re25 88.0 2793 4765 1.2 Swift A Frame 275 3.520 94.5   H1000 88.0 2719 4514 1.1 Swift A Frame 275 3.520 94.5   IMR7828SSC 85.0 2806 4809 1.2 Swift A Frame 275 3.520 94.5   Viht N560 85.5 2820 4855 0.9 Nosler AccuBond 300 3.600 89.7   MagPro 84.5 2549 4329 1.4 Nosler AccuBond 300 3.600 89.7   Re25 83.5 2498 4158 1.3 Nosler AccuBond 300 3.600 89.7   H1000 86.0 2593 4480 1.0 Nosler AccuBond 300 3.600 89.7   IMR7828 80.5 2647 4669 1.1   Remington’s Model 700 XCR II Part 1 Remington’s Model 700 XCR II Part 11