Primer Question

[ryantx23]

Does anyone know if CCI Magnum 350 Large Pistol primers can be used regular pistol rounds? If so, how much of a powder reduction is needed? Any help would be appreciated. Thanks

[Dracos]

Magnum primers are used for large charges of slow burning powders. Also some people use them for reliable ignition in very cold weather. The SOP is to back off one grain and carefully work up watching for signs of high pressure, gas leaking around primer, flattened primer, etc.

[explorer1]

Just my 2 cents but if I were loading with mag primers, I would start off 10% below normal loads and work-up from there, still watching for the above signs.:)

[Hummer]

Magnum primers generally have a thicker cup to control the higher pressures. If your striker energy is marginal you may get erratic ignition. Handguns by their very nature generally lack the ability to deliver heavy and fast striker velocity.

The 1911A1 is the exception as it has striker energy up the yeng yang.

Primer energy is measured using copper cylinders in special holders that look like headspace gages. Two energy levels I know off the top of my head are for 38 and 357 Mag. The federal revolver spec for 38 special requires a .009" copper indent while the federal revolver spec for 357 Magnum requires .011" indent or deeper.

The US Border Patrol Spec requires .011" indent in both single and double action. As well the specification calls for the revolver to be in time for 10,000 rounds and striker indent centrality to overlap the center of the primer by 1/3rd. There is also a headspace requirement and barrel cylinder gap requirement.