How exactly do you use chronograph to figure over pressure problems with reloads?

I've found the velocities listed in the manuals rarely match up with real world velocity. For that reason, you probably couldn't use a chronograph to reliably gauge pressure. Flattened primers and sticky extraction are far better indicators of pressure problems.

Well, now that I think of it, if you are experiencing huge velocity variations, that's a sign of not quite enough pressure for that powder to burn properly.

Loading for bolt guns, I've found a chronograph to be pretty helpful, especially when following Sierra load data. I'm usually right with their velocities as they use everyday weapons instead of insanely tight test barrels. Chronographs have a place. If the loading manual suggest 1250 fps for a max load and x amount of grains of powder; and your seeing 1500 fps and extraction is difficult, you may want to back it off.

Not all flat primers are a good indication of pressure. If your headspace is off, the cartridge will slam back into the bolt face. The same with cratered primers, a sharp firing pin will cause that.

In short, the only sure fire way to determine pressure is they way they create loading manuals with modified cases and gauges. Not many people, including myself, can accurately call pressure. There are just too many variables.

It is fun to experiment though...

Brenden

deerdad,

A chronograph can not be used to give you over pressure information directly. However, as an indirect indicator, velocities in the range of published ( reputable loading manuals ) implies that pressures are within acceptable limits. If velocities are above those published in the data, the loads are probably approaching or over pressure. Pressure is dependent upon multiple factors / variables.

Doc