Bulge
 

I have a little 1 frame PH 12 ga with twist barrels I picked up in a trade. It has a small bulge just ahead of the forcing cone at about the 10 o'clock position in the left barrel. I didn't notice it when the trade was in progress (I am glad I didn't or I might have not gone through with the deal). It is barely perceptible to the touch or the eye. I use light loads and don't worry about it. It is just a fun little gun to shoot and it hammers roosters. It is my oldest Parker yet has dimensions that are very close to 'modern' and is very shootable. That may be because it has a Parker replacement stock from the Twenties.

Jeff, That sounds like my situation. The bulge is right at the 10 o'clock position and I actually bought this gun for Julia and we have both shot it, although she has lost interest in it. All the responses here make me feel a whole lot better about it.