1 of 1 .275 Rigby factory loads carry 1,000 ft·lb and expansion velocity for whitetail deer; the best reach 400 yd (Hornady Custom 140 gr SP InterLock). Ranked, with the drop chart for each.
| Load | gr | Max ethical yd | MV fps | 500 yd ft·lb | Shoulder shot |
|---|---|---|---|---|---|
| Hornady Custom 140 gr SP InterLock | 140 | 400 | 2,680 | 850 | behind the shoulder only |
The 1,000 ft·lb deer figure traces to Townsend Whelen and is the one everyone repeats; Hawks puts the floor nearer 800. An 8–10″ heart/lung zone. Legal: CO: 1,000 ft·lb at 100 yd · SD: 1,000 ft·lb at muzzle. Floor used: 1,000 ft·lb at impact plus the bullet's published expansion velocity. Orange = a target or varmint bullet (construction, not energy); red = never carries the energy. Sources: www.outdoorlife.com, www.petersenshunting.com, chuckhawks.com.