The 338 Weatherby RPM, or Rebated Precision Magnum, is a powerful rifle cartridge developed by Weatherby in 2022 by necking up the 6.5 Weatherby RPM to provide magnum-level performance in a shorter, lighter 6-lug action rifle. This design delivers velocities and energy comparable to the 338 Winchester Magnum while allowing for more compact and portable firearms, making it ideal for backcountry hunters targeting large game like elk, moose, and bears. This article focuses specifically on ballistics, examining external factors like trajectory, wind drift, and energy retention, as well as wound ballistics to offer practical insights for reloaders and hunters. Both supersonic loads, which dominate this caliber, and their terminal effects will be analyzed to help you choose the right bullet for your needs. Whether for big game or long-range shooting, understanding these aspects ensures ethical and effective shots. For a broader overview, check our complete guide to the 338 Weatherby RPM.
Core External Ballistics
The 338 Weatherby RPM accommodates bullet weights from 185 to 250 grains, with muzzle velocities ranging from 2600 to 3100 feet per second depending on the load. This versatility suits various hunting scenarios, from lighter bullets for flatter trajectories to heavier ones for deep penetration on large game. Supersonic loads are standard, offering flat trajectories and high energy delivery, though subsonic options are less common and not typically emphasized. High-level data indicates average muzzle energy around 3700 to 4000 foot-pounds, with ballistic coefficients varying from 0.432 for basic copper projectiles to 0.600 for match-grade options. For comparisons with similar calibers, see our 338 Winchester Magnum ballistics and 338 Lapua Magnum ballistics.
Bullet Drop to 1000 Yards
| Range (yards) | 185gr (inches) | 225gr (inches) | 250gr (inches) |
|---|---|---|---|
| 100 | 0 | 0 | 0 |
| 200 | -2.3 | -2.7 | -3.0 |
| 300 | -9.2 | -10.8 | -12.0 |
| 400 | -21.0 | -24.5 | -27.0 |
| 500 | -38.0 | -44.0 | -48.5 |
| 600 | -63.0 | -73.0 | -80.0 |
| 700 | -97.0 | -112.0 | -123.0 |
| 800 | -144.0 | -166.0 | -182.0 |
| 900 | -207.0 | -239.0 | -262.0 |
| 1000 | -278.0 | -320.0 | -351.0 |
The bullet drop data reveals the 338 Weatherby RPM’s flat trajectory out to 300 yards, where drops remain manageable under 12 inches for all weights, allowing for straightforward aiming adjustments in typical hunting situations. Beyond 400 yards, drops accelerate, exceeding 25 inches, which demands precise range finding and holdover skills. Heavier bullets like the 250gr show more drop at mid-ranges but comparable retention at extended distances due to superior ballistic coefficients, maintaining usability out to 1000 yards for skilled shooters, while lighter 185gr loads fall off faster, limiting their practical range to 600 yards. This caliber’s limitations begin around 500 yards for ethical hunting, where gravity significantly impacts accuracy on game. Realistic ranges for hunting include 300-400 yards for elk and 200-300 for defensive shooting, with heavier loads extending this for experienced users. For more on extended charts, explore our long-range hunting calibers guide.
Wind Drift (10 mph Crosswind)
| Range (yards) | 185gr (inches) | 225gr (inches) | 250gr (inches) |
|---|---|---|---|
| 200 | 2.6 | 2.4 | 2.2 |
| 300 | 6.8 | 6.2 | 5.7 |
| 400 | 13.0 | 11.8 | 10.8 |
| 500 | 20.0 | 18.2 | 16.7 |
| 600 | 33.0 | 30.0 | 27.5 |
| 700 | 48.0 | 43.5 | 40.0 |
| 800 | 64.0 | 58.0 | 53.0 |
| 900 | 80.0 | 72.5 | 66.5 |
| 1000 | 97.0 | 88.0 | 80.5 |
Bullets with higher ballistic coefficients, such as the 225gr and 250gr options, resist wind drift better, showing 8-16 inches less deflection at 1000 yards compared to lighter loads. This makes them preferable for open-country hunting where crosswinds are common. Wind affects practical accuracy significantly beyond 300 yards, where drifts exceed 6 inches, requiring wind calls within 2 mph for consistent hits. At 500 yards, drift reaches 17-20 inches, making wind reading unreliable without tools like Kestrels. Supersonic loads maintain stability in wind better than subsonic, though the latter are rare in this caliber. Realistic expectations include compensating for 10-20 inches at 500-700 yards, with heavier bullets extending effective range. For wind-related tips, refer to our big game hunting caliber guide.
Energy Retention
| Range (yards) | 185gr (ft-lbs) | 225gr (ft-lbs) | 250gr (ft-lbs) |
|---|---|---|---|
| 0 | 3947 | 3765 | 3650 |
| 100 | 3397 | 3230 | 3130 |
| 200 | 2913 | 2750 | 2660 |
| 300 | 2486 | 2330 | 2250 |
| 400 | 2110 | 1960 | 1890 |
| 500 | 1778 | 1640 | 1570 |
| 600 | 1490 | 1360 | 1300 |
| 700 | 1240 | 1120 | 1070 |
| 800 | 1030 | 920 | 880 |
| 900 | 850 | 750 | 720 |
| 1000 | 700 | 610 | 580 |
Energy decays steadily, dropping below 2000 foot-pounds by 400 yards for most loads, with lighter bullets losing velocity faster due to lower sectional density. Heavier 225gr and 250gr options retain more energy at distance, staying above 1000 foot-pounds out to 700-800 yards, ideal for larger game. Supersonic loads deliver high initial impact, but subsonic variants, if used, would show rapid energy loss. Ethical hunting ranges are 300-500 yards for elk, where energy exceeds 1500 foot-pounds for reliable expansion and penetration. Certain loads fail to expand below 1800 fps, around 500-600 yards, risking poor terminal performance. Structured analysis highlights the importance of matching load to game size for humane kills. For more on energy dynamics, see our hunting caliber selection guide.
Wound Ballistics (Expanded Practical Section)
Bullet design plays a critical role in the 338 Weatherby RPM’s terminal performance, as high velocities promote rapid expansion while construction determines penetration and wound channel size. Supersonic bullets create hydrostatic shock for faster kills, differing from subsonic in tissue disruption, though subsonic use is uncommon here. The goal is to provide practical guidance on how these loads perform in real hunting scenarios, aiding bullet selection for ethical outcomes. For detailed gel-testing insights, explore related breakdowns in our site resources.
Bullet Performance Profiles (5 Most Common Loads)
Barnes TTSX
- Type – All-copper, monolithic for deep penetration
- Behavior – Expands consistently in tissue, producing broad wounds with high trauma at velocities above 2400 fps
- Use – Ideal for large bodied game like bears and moose
- Effective Range – 50-500 yards
- Short Summary – Reliable for close to moderate ranges, ensuring pass-through on tough animals.
More details available in our dedicated bullet profile page Barnes TTSX bullet.
Nosler AccuBond
- Type – Bonded core with polymer tip for accuracy and expansion
- Behavior – Fast expansion above 2600 fps, with delayed killing at lower speeds, often shedding weight on heavy bone
- Use – Best for medium to large deer and elk species
- Effective Range – 100-400 yards
- Short Summary – Provides clean kills on large bodied game with balanced performance.
More details available in our dedicated bullet profile page Nosler AccuBond bullet.
Hornady ELD-X
- Type – Polymer tipped, bonded for controlled expansion
- Behavior – Reliable expansion in gel, creating wide wound channels with good weight retention on medium to large game
- Use – Suited for big game like elk and moose
- Effective Range – 100-600 yards
- Short Summary – Versatile for long-range hunting, balancing penetration and trauma.
More details available in our dedicated bullet profile page Hornady ELD-X bullet.
Berger Elite Hunter
- Type – Hybrid design for long-range accuracy and expansion
- Behavior – High trauma with fragmentation in vitals, suitable for precision shots
- Use – Effective for deer and elk at distance
- Effective Range – 200-700 yards
- Short Summary – Optimized for ethical long-range harvests on mid to large game.
More details available in our dedicated bullet profile page Berger Elite Hunter bullet.
Federal Trophy Bonded
- Type – Bonded jacketed soft point for deep penetration
- Behavior – High trauma at close ranges, with hydrostatic shock above 2600 fps on vitals
- Use – Suited for moose and larger game
- Effective Range – 50-300 yards
- Short Summary – Excels in stopping power for big game at ordinary distances.
More details available in our dedicated bullet profile page Federal Trophy Bonded bullet.
Practical Summary
For predators and varmint, lighter bullets like the 185gr Barnes TTSX fit well, offering explosive expansion at high velocities. For hogs and deer, opt for 225gr Nosler AccuBond or Berger Elite Hunter, which provide deep penetration and reliable wound channels. Larger game like elk and moose benefits from 250gr Hornady ELD-X for maximum energy transfer. Subsonic suppressed use is not typical for the 338 Weatherby RPM, as it excels in supersonic applications; consider the 300 Blackout for that. Range discipline is essential, as excessive distance risks poor terminal performance despite the caliber’s flat trajectory. Bullet choice defines terminal results more than velocity alone, prioritizing construction for game size over raw speed. To dive deeper into ballistic and gel-test materials, explore our 300 Blackout ballistics, best reloading dies, and small game caliber guide.
Readers are encouraged to explore related articles for deeper analysis, such as our 338 Winchester Magnum ballistics, detailed wound ballistics breakdowns, gel-testing results, extended ballistic charts, and individual bullet reviews and comparisons.
