11 of 11 .280 Ackley Improved factory loads carry 800 ft·lb and expansion velocity for pronghorn; the best reach 950 yd (Federal 155 gr Terminal Ascent). Ranked, with the drop chart for each.
| Load | gr | Max ethical yd | MV fps | 500 yd ft·lb | Shoulder shot |
|---|---|---|---|---|---|
| Federal 155 gr Terminal Ascent | 155 | 950 | 2,930 | 1,583 | yes |
| Hornady Precision Hunter 162 gr ELD-X | 162 | 950 | 2,850 | 1,674 | yes |
| Nosler Trophy Grade Long Range 150 gr AccuBond Long Range | 150 | 900 | 2,930 | 1,504 | yes |
| Federal 140 gr Trophy Copper | 140 | 850 | 3,075 | 1,438 | yes |
| Barnes VOR-TX LR 152 gr LRX BT | 152 | 750 | 3,000 | 1,422 | yes |
| Nosler Expansion Tip 140 gr E-Tip | 140 | 750 | 3,200 | 1,576 | yes |
| Nosler Trophy Grade 140 gr AccuBond | 140 | 750 | 3,200 | 1,566 | yes |
| Nosler 140 gr Ballistic Tip Hunting | 140 | 700 | 3,100 | 1,456 | behind the shoulder only |
| Nosler Trophy Grade 160 gr AccuBond | 160 | 700 | 2,950 | 1,589 | yes |
| Federal 168 gr Berger Hybrid Hunter | 168 | 650 | 2,800 | 1,574 | behind the shoulder only |
| Nosler Trophy Grade 160 gr Partition | 160 | 600 | 2,950 | 1,459 | yes |
Chuck Hawks: ~800 ft·lb at impact with a .24″+ bullet of SD ≥ .215. Legal: CO: 1,000 ft·lb at 100 yd (rifle). Floor used: 800 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.chuckhawks.com, cpw.state.co.us.