An M-80 ball round will deliver much less penetration at close range than it will at longer range, say, past fifty or seventy-five yards. It takes that long for that 147 gr. bullet to settle down and fly point first, without the boat-tail end dancing around. This is common with any bullet fired through a barrel with too fast a twist for that bullet weight. The same thing happens with M-193 55 gr. bullets fired in a 1/9 or a 1/7 twist. To a lesser extent, same thing with the 62gr M855 bullet in a 1/7 twist M-16A2. Back that log off to 100 yards and I would be surprised if BOTH rounds didn't zip right through.
Thing is, however, the M-80 would probably zip right through a SECOND 10" log at that range, with enough force to kill. The M-855 would be stuck in the second log.
I have shot an awful lot of trees in my time, with both calibers at short and long range. The 30 caliber is vastly superior. The 198gr 7.92 mm Mauser round will out penetrate either and the greatest penetration I have ever seen in wood was by the 7mm Mauser with the old 175 gr metal cased bullet. I couldn't fine a tree big enough to stop it, at any range.
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