280 Ackley Improved Load Data & Ballistics Calculator
Estimate chamber pressure and muzzle velocity for the 280 Ackley Improved with the free,
in-browser MyLoads internal ballistics simulator. The figures below are illustrative
estimates from a physics model — not a recommended load. Always cross-check a current
published loading manual.
280 Ackley Improved reference
Maximum average pressure (MAP)
65,000 psi
Nominal case capacity
71.5 gr H₂O
Groove / bullet diameter
0.284 in (7.21 mm)
Example simulation illustrative
Bullet
Hornady 0.284 162 gr InterLock BTSP
Powder
IMR 7828 SSC
Charge
54.8 gr
Barrel
24 in
Muzzle velocity
2,720 fps
Peak chamber pressure (interval, ±10% burn rate)
43,131 – 53,115 – 64,239 psi
nominal is 82% MAP (65,000 psi)
Illustrative example — every figure is an estimate; always confirm your load against a current published manual before loading.
Popular 280 Ackley Improved powders
Powders and bullets handloaders commonly use for the 280 Ackley Improved, drawn from public discussion and listed most common first. They appear as the Popular group in the calculator's pickers. This is not a load recommendation — always check your load against a current published manual.
Hodgdon H1000
Hodgdon Retumbo
Hodgdon H4831SC
IMR 7828 SSC
Alliant RL-26
Alliant RL-23
Alliant Reloder 16
Vihtavuori N560
Accurate MagPro
Norma MRP
Alliant RL-25
Popular 280 Ackley Improved bullets
Hornady 0.284 162 gr ELD-X
Nosler AccuBond 7mm 160 gr Spitzer
Berger 7 MM 168 gr VLD Hunting
Nosler Ballistic Tip Hunting 7mm 140 gr Spitzer (Red Tip)
Berger 7 MM 175 gr Elite Hunter
Nosler Partition 7mm 160 gr Spitzer
Barnes .284 145 gr LRX BT
Barnes .284 150 gr TTSX BT
Nosler AccuBond Long Range 7mm 150 gr Spitzer
Nosler Ballistic Tip Hunting 7mm 120 gr Spitzer (Red Tip)
Hornady 0.284 175 gr ELD-X
Speer Hot-Cor Spitzer SP .284 160 gr
Use MyLoads as a 280 Ackley Improved velocity and pressure calculator: it estimates
muzzle velocity, muzzle energy and the full chamber-pressure curve for your own powder,
charge and barrel length, compared against the reference facts above.