MyLoads Open the calculator →

6mm GT Load Data & Ballistics Calculator

Estimate chamber pressure and muzzle velocity for the 6mm GT 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.

6mm GT reference

Maximum average pressure (MAP)62,000 psi
Nominal case capacity42.0 gr H₂O
Groove / bullet diameter0.243 in (6.17 mm)

Example simulation illustrative

Bullet
Sierra 6mm 243 Caliber (.243) 107 gr HPBT-CN MatchKing
Powder
IMR 4064
Charge
30.8 gr
Barrel
24 in

Muzzle velocity

2,682 fps

Peak chamber pressure (interval, ±10% burn rate)

39,718 – 49,591 – 60,421 psi

nominal is 80% MAP (62,000 psi)

The simulator isn't optimized for this cartridge yet and may read pressure high.

Illustrative example — every figure is an estimate; always confirm your load against a current published manual before loading.

Popular 6mm GT powders

Powders and bullets handloaders commonly use for the 6mm GT, 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.

Popular 6mm GT bullets

Use MyLoads as a 6mm GT 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.

Open the 6mm GT in the MyLoads calculator →

More cartridges