Crack in VH barrel?

[edgarspencer]

For piece of mind, you can use any of several NDT (Non Destructive Testing) methods to determine if what you're seeing is a real crack.
These methods include Radiographic inspection, Liquid penetrant inspection, Magnetic particle inspection or shear wave ultasonic inspection.
All of these can be performed by any of several nationwide testing companies, such as MQS, who have labs in all major manufacturing areas.
All, except Liquid penetrant, require expensive testing equipment, and are done by trained NDT, level II or Level III inspectors. You can buy a relatively inexpensive Liquid Penetrant test kit at most welding supply houses, and the basic test is not difficult, though level of severity in a detected result is only gotten from training and experience.
A less definitive test, but more a go-no go test is to use kerosene, which has a very low surface tension. Pour some kerosene down the barrel, making every effort to keep it from coming in contact with the outside. Allow it to sit a few minutes, drain it off, and dust the outside with baby powder. The kerosene will come through all but the tightest knit crack, and the baby powder will immediately absorb any that came through, showing a crack.