What is a good Brinell hardness for 9mm?

[buenhec]

I have recently started shooting lead to offset other costs. I steel shoot with a CZ75 Shadow and load 124g lead RN with 4.0 of VV N320.

At the last match after 300 rounds my gun would not go into battery. I took it apart, brushed and oiled and it worked fine. It was pretty cruded.

300 rounds does not seem like much. My bullet maker claims a Brinell of about 13. Is this too hard or soft? How hard should he make them to avoid this? Or is it normal with all lead shooting?

 

[evan price]

What type of crud was it?

If it was black gritty gunk it was powder residue. If your brass is sooty it may be your charge is too light and you are not getting enough pressure to fully allow the brass to seal the chamber on firing.
I don't use VV powder but I've heard N320 is close to the Titegroup I use, and I found that it likes heavier charges in 9mm because it is so fast of a powder.

 

[Walkalong]

4 Grs of N320 should not crud up a gun from powder residue.

I would go with N330 here over N320 though. WSF is even a better choice.

Nothing wrong with the N320 load though.

Bullets may be too hard, not too soft. Need more info.

 

[TexasSkyhawk]

Hardness isn't as important as proper sizing.

Measure your bullets before you load them into the cases. Should be .356. If they are smaller--and hard cast--you're probably going to get some leading. Bad lube will also contribute to the "crud."

And finally, if you're using an FCD on your reloads, this can actually swage a lead bullet down in size, thus causing a smaller diameter and subsequent leading potential.

Jeff

 

[depoloni]

Properly sized (great mention sir) and lubed, of course, I shoot a TON of 9mm cast 122gr truncated cone bullets in my CZ-75B.

I've used the Lee hardness testing kit, literally dozens of times and on an equal number of bullets, and although it's a bit funky to use I consistently keep getting BHN measurements of about 21. That's pretty hard - but I love it and so does my pistol. I can push those bullets, in my pistol, to 1120fps (and whatever pressure that equals, it's not near max) ahead of 231 or bullseye with no leading problems whatsoever. Often my wife and I shoot 150 rounds in a session without cleaning and have had no problems.

I had a batch of 500 cast 125's I bought awhile back and loaded, which measured closer to 16, and they started leading significantly anywhere between 980 and 1050fps in the same pistol with the aforementioned 2 powders. Again, whatever pressures, but not near max. Sized the same, just softer.

Leading depends on a lot of things - bore roughness, pressure, bullet vs. bore sizing, lube... but I find that modern autos geared to grip and spin jacketed bullets have no problems doing the same with harder-cast lead, so I go hard. In the end if it only gives me more wiggle room with loads before leading problems. Good luck.

Incidentally, the most accurate loads behind said cast bullets are at around 1000fps in my pistol with either powder actually.

 

[Down South]

BHN of 12 should be OK. That about what WW is without anything added or heat treating. If your crud was lead then you have a problem. A lot of leading problems are due to undersized boolits. A comment was made up above about the Lee FCD and it is true. The FCD can actually swage a boolit down and make it too small. You really should slug your barrel. You cast boolit should be .001 to .0015 larger than your bore. Too high velocity can be a problem too. Have you clocked your load?