Finding correct load data

[rustyb]

I'm having trouble finding correct load data. I have 9mm 124gr plated bullets and power pistol. I have hornady and lyman pistol manuals and they list max load for 124gr bullets at 5.7 and 5.6 gr respectively.

Several online sources list higher charges. Most I have found online list max charge at 6.6 gr and alliant site lists 6.4gr.

Help me please.

 

[rral22]

Start with an average of the "medium" loads from all your manuals, and then work up and test loads in small increments until you either reach "maximum load averages" without problems, or you experience indications of serious pressure. That's what everyone does.

 

[IMagius]

Start with an average of the "medium" loads from all your manuals, and then work up and test loads in small increments until you either reach "maximum load averages" without problems, or you experience indications of serious pressure. That's what everyone does.

x2 ... though I would stop at the first warning sign of any high pressure, and not wait for "serious" pressures to develop.

I know what rral meant, but wanted to clarify that just in case someone else didn't.

 

[prosper]

often with a handgun, the first sign of pressure is a 'kaboom.' Primers and brass often don't show any signs of high pressure until you're into the 70,000 psi range. For most rifle cartridges, this is only about 10% over max, so is usually not too concerning. But for a pistol or revolver, this is at least twice where you should be.

Best test is to start low and work up, shooting them over a chrony until you're into 'established' muzzle velocities for your cartridge and barrel length.

 

[Suputin]

And this is why we have chronographs.

 

[Ganderite]

I start at the Start load and load up in 0.3 increments, looking for the threshold that will operate the gun and then the load that groups best. There can be huge differences in group size. Seldom is the best laod near max.