There are plenty of people who shoot like that at 10 feet with any gun. Including me on a bad day.
Any firearm, when shot with excessive amounts of lead ammo, will have leading problems. That's just the nature of it.
I wouldn't call a couple hundred rounds of 22LR excessive. It might not
even have been that much, now that I'm thinking of it. FWIW, this
same gun typically would have at least an entire brick of golden bullet
run through it, and at least at the end of the session would still be hitting a
target at 20 feet no problem.
And I was -there- when it happened, so it wasn't just him missing the
target... because I loaded the gun up and I got similar results. At first
I tried to shoot at the target from about 25 feet and missed completely, and
then I think I had to get within 10 feet to hit paper... the holes we were
getting on target defied logic. I think some of them even keyholed, like
the bullet was coming out of the barrel and turning sideways. After
a few mags of futility I cleared the gun and looked at the barrel, and it
was polluted with lead.
-Mike