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Common uses: Hunting, Big Game, Long Range
| Type | rifle (centerfire) |
| Typical load | 180gr Remington Premier Scirocco Bonded |
| Muzzle velocity | 3250 fps |
| Muzzle energy | 4223 ft-lb |
| Published G1 ballistic coefficient | 0.5 |
| Case length | 72 mm |
| Overall length | 95 mm |
| Range (yd) | Velocity (fps) | Energy (ft-lb) | Drop (in) |
|---|---|---|---|
| 0 | 3250 | 4221 | -1.5 |
| 100 | 3045 | 3706 | 0 |
| 200 | 2850 | 3246 | -2.3 |
| 300 | 2663 | 2835 | -8.8 |
| 400 | 2485 | 2467 | -20.3 |
| 500 | 2313 | 2138 | -37.3 |
At 1,000 yards, .300 Ultra Mag (180gr at 3250 fps, 100 yd zero, standard conditions) has a modeled come-up of about 23.4 MOA / 6.8 MIL, retaining 1562 fps (supersonic).
| Range (yd) | Velocity (fps) | State | Drop (in) | Elev (MOA) | Elev (MIL) |
|---|---|---|---|---|---|
| 300 | 2663 | Supersonic | -8.8 | 2.8 | 0.82 |
| 400 | 2485 | Supersonic | -20.3 | 4.8 | 1.41 |
| 500 | 2313 | Supersonic | -37.4 | 7.1 | 2.08 |
| 600 | 2148 | Supersonic | -60.9 | 9.7 | 2.82 |
| 700 | 1989 | Supersonic | -92.2 | 12.6 | 3.66 |
| 800 | 1839 | Supersonic | -132.0 | 15.8 | 4.58 |
| 900 | 1696 | Supersonic | -182.3 | 19.3 | 5.63 |
| 1000 | 1562 | Supersonic | -244.7 | 23.4 | 6.80 |
Extended predictions beyond 500 yards are modeled from the same G1 engine — useful for initial DOPE, but outside the 500-yard manufacturer-table validation audit. Confirm with observed DOPE, especially near transonic.
A retained-energy reference only — not a shoot/don't-shoot distance. Real effective range depends on your accuracy, shot placement, bullet construction, and conditions. The ~1,000 ft-lb (deer-sized) and ~1,500 ft-lb (elk-sized) figures are commonly cited rules of thumb, not standards.
Your barrel, ammunition lot, and conditions will differ — always verify against the manufacturer's data and your own rifle.
The .300 RUM is known as one of the most powerful factory .30-caliber cartridges, prized by hunters who want flat trajectories and heavy retained energy on large game at extended range. It excels on elk, moose, bear, and other big North American animals, and its high velocity makes it a capable long-range option with heavy, high-BC bullets. That performance comes at a steep cost: recoil and muzzle blast are severe, and the large powder charge burns out barrel throats noticeably faster than more moderate .30 magnums. It is generally regarded as more cartridge than most deer-sized game requires, so it appeals mainly to shooters who genuinely need maximum reach and energy rather than all-around versatility. Reloaders in particular value it for the flexibility its large case offers, since factory ammunition is less common and more expensive than mainstream magnums.
Remington introduced the .300 Remington Ultra Magnum (.300 RUM) in 1999 as the flagship of its beltless Ultra Magnum line. The case is derived from the large .404 Jeffery, blown out and necked down to .30 caliber, giving it one of the largest powder capacities of any commercial .308-diameter cartridge. Unlike the older belted magnums, it uses a beltless, rebated-rim case that headspaces on the shoulder, and it was designed to push heavy .30-caliber bullets to the highest velocities then available in a factory .30-caliber magnum.
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