LyleK

I measured the bore with a set of calipers (not an expensive set mind you) and it is close to .501, which is the initial source of my concerns.

The gun is only a few years old. I purchased if from a friend earlier this year. I clean the gun with either Bore Cleaner or sometimes I use window washer fluid.

I swab with T/C Bore Butter Cleaning Patches between shots most of the time. On ocassion i will use the window washer fluid and dry patches if i think that the bore is getting a little fouled.

When completed for the day, i do use a bore brush and bore cleaner. Bore Butter cleaning patches follow.

Could there be a buildup in the barrel?