Copper plated cast bullets

[oldsagerat]

Several companies offer copper plated cast or swaged lead bullets. My question is how soft
is this coating? Can I treat these just like normal cast bullets when it comes to the diameter
of the bullet versus the groove diameter of the barrel. I have a Cz-527 in 7.62x39 that has a
groove diameter of .311 and I normally shoot .311 cast or jacketed bullets. I have a lot of plated
bullets that are .312 diameter. Should I swage them down to .311 before shooting them?
Is the .001 inch diameter difference of no concern? Will I get a pressure spike?

Just being cautious.

[dondiego]

You should be able to shoot those plated 0.312 bullets with no issues. Start low and work up a load.

[3leggedturtle]

I have shot them, pistol .357 and .452 diameter bullets up to a chronoed 1800fps with no problems. If you are able to chamber them I wouldn't resize them. My 30/30 would chamber the .312"s so haven't loaded those yet. Todd/3leg

[Tatume]

The copper plate is probably only a few molecules thick. Do you have a hardness tester? I suspect you will find them to be around 18 - 20 BHN (the hardness of the cast bullet underneath). As soon as I get a few minutes to call my own, I'll check.

[DR Owl Creek]

As others have said, plated bullets generally shouldn't be a problem. Not all plated bullets, however, are created equal. Most plated bullets have a soft lead swaged core, with varying thicknesses of plating, depending upon the manufacturer. Some other plated bullets, however, like the Speer "Gold Dot" and "Deep Curl" designs have a heavy plating, along with cores made from harder alloys, to control penetration and expansion, so these should be treated like normal jacketed bullets.

Dave

[mdi]

Yep, "normally" plating is done on a soft lead bullet and it's very thin, my guess would be .001" and mebbe .0015". I shoot plated bullets just like I shoot cast lead bullet; size and loads.

Berrys offers some bullets with thicker plating, "TP", that are advertised to achieve higher velocities...

[runfiverun]

your extra .001 is of no concern unless it won't chamber.

[sigep1764]

Before I started casting, I used Zero brand copper plated bullets exclusively because they were cheaper. I was told to use cast boolit data because of the thin plating and never had a problem. Just work the load up like normal using the cast load data for your given powder. Had no problem driving them to 1200 fps in 9mm.

[oldsagerat]

Thanks everyone. As usual, you are very helpful.