Need to reduce load Commercial 7.62x51 NATO?

[Peter_Kirch]

I bought a bunch of Commercial Winchester 7.62x51 Nato rounds. To reload the brass do I need to reduce the loads like standard mil surp brass or load like a regular 308 cartridge. Also how do I check the internal volume? I thought about water but wont that seep into the flash hole throwing off the measurement?

[tammons]

You should ask around a bit more, but from what I understand its no problem.

The 308 runs at 60k and the nato at 55k.

As far as measuring the capacity of brass I just leave the primer in and mark it wet with a sharpie to make sure it does not end up
loaded with a bad primer.

[BillPa]

. Also how do I check the internal volume? I thought about water but wont that seep into the flash hole throwing off the measurement?


The standard SOP for measuring cartridge volume is using water with a drop or two of detergent to break the surface tension and a bullet seated. Water conforms to the cartridge interior the same as the expanding powder gasses, so the standard capacity is referenced as "grains of H2O".

Since the gasses fill any empty space the flash hole capacity is included in the interior volume measurement. The bullet seating depth also affects the volume.

To get a accurate measurement, seat the bullet to it's intended depth, weigh the cartridge then fill it with water through the flash hole using a hypodermic needle or something that will fit the flash hole and still allow the air to escape around it. Remove any overfill in the primer pocket and re-weigh. The difference between the two weights is the interior volume in grains of H2O. Do about 20 randomly selected cartridges and you'll get the average for that manufacturer and lot of brass.

Bill