The old hevi 13 were 13g cc now they have dropped to around 12g cc.

Andy, I believe this is due to the irregular shape of the pellets.

Only thing you will find better are NITRO shells (Production wise)..... they are about $8-$10 per shell.

I agree 100%. They are $6 around here.

This is news to me, when did this happen? I was under the impression that Hevi-Shot was 12g cc but Hevi-13 was 13g cc? Is this not the case?

HEVI-13 states "HEVI-13 pellets are about 20% denser than lead and penetrate far deeper." Lead density is 11.3g cc, so 20% denser would be 13.5 g cc. I could swallow 13 g cc, but if they are advertising their shot is 20% denser than lead and producing and selling something that is 6% denser, that is very misleading.

These have always been the density values that I learned and used in my calculations:

Steel - 7.5g cc, Bismuth - 9.6g cc, Unplated Lead - 11.3g cc, Hevi-Shot & Remington HD - 12g cc, HEVI-13 - 13g cc, Federal heavyweight - 15.2g cc, and Tungsten Super Shot - 18g cc.

I agree 100% and so does my good friend who has been shooting Nitro's since they first hit the market 10 or more years ago. We both agree the irregular shape of the shot is a key player in the killing power, as well as the denser shot, thus more penetration at similar velocities.

....if handloaders had not measured the density.

Deformed shot causes flyers.

Square bullets wouldn't kill any better than round ones...