Perplexing divots in .410 bore

[A&Shuntr]

I've been around firearms a long time and I have never seen such a bizarre set of marks in a chamber area. On a Steven's 22-410 the forcing cone has one large gouge and three smaller on the lower side, looks like a .25cal bullet ricochet as it is enlongated lengthwise about 1/32" deep and displaced slightly metal up around the edges. The smoothness of the divots lead me to believe they were not mechanically made by screwdrivers or cleaning rods etc.. I wish my bore scope could take pictures as I would post them. The gun I know for a fact has not been shot for 40 years so this precludes any of the "buck shot or self defense" type loads or steel been fired in it. It is not a large enough defect to render it unsafe but it is very peculiar. Anyone seen such a thing before and what have caused it?

 

[tiriaq]

Maybe someone did something stupid with homemade buckshot loads using ball bearings...

 

[mooncoon]

I am wondering if someone used something sharp to try to remove the front end of a broken case and the smoothness is more by chance

cheers mooncoon

 

[sunray]

It doesn't take much to make a barrel unsafe to shoot. A 1/32" groove in a thin barrel makes a weak spot.