Lead buildup in .22LR Revolver

[Skinny 1950]

I bought a used Ruger Single Six revolver and cleaned it up before heading to the range. When I was cleaning it a sheet of lead came out of the barrel where it meets up with the cylinder. The piece of lead was about 1/2 inch long by 1/4 inch wide and about 3-5 thousands thick. I cleaned the barrel as best I could and it was nice and bright.
I took it to the range a couple of times and shot 150-200 rounds through it and when I cleaned it another big chunk of lead came out from the same place.
Does anyone know what I can do about this if it keeps happening,and should I clean the oil out of the barrel before shooting.Thanks
Here is a picture of my revolver.

 

[legi0n]

That looks like an extreme case of bullet shaving. The cause? Most often the cylinder is out-of-time. Meaning that at least one chamber does not align with the bore.
Have a gunsmith examine your piece.

 

[Yogi05]

I had the same thing with a Herbert Schmidt SA revolver. The cleaning rod I use to check for obstructions wouldn't go all the way into the cylinder. A quick jab and a small sliver of lead flew out. Not as large as described above, but it shouldn't be there. In my case it only happened the one time so I blamed it on less than perfect bullet shape. I have been watching for a timing issue but so far it happened only the one time.

My question.... when does a timing issue become dangerous? Immediately? Or can an isolated incident like mine be a matter of one misshaped bullet? And how is cylinder timing fixed?

 

[Until the Angels Fall]

x2 for a gun smith check up

 

[Skinny 1950]

I was thinking it might be a timing issue so I examined each chamber and it looked fine, the previous owner did not take very good care of this gun and the lead chunks may be the result of never cleaning it.
I am going to take it to a gunsmith anyway, I think my ATT covers that but I will check. Thanks for the input on this.....