I have a gun with a slight bulge about midway down the left barrel. I have seen guns blown out there but I intend to shoot this gun with low presure loads and because of a shoulder injury, I keep my forward hand at the back of the forarm away from immediate danger. The barrel has a 1912 full choke so I am thinking I should have it opened to modified, improved cylinder or cylinder to reduce pressures even more? What advice on the chokes and pressure can you offer? Thanks very much. Kurt

I seriously doubt choke had anything to do with the bulge....most likely an obstruction.

What you have is a shoot at your own risk gun.

From what I understand, opening the choke will not alter the pressure as the pressure is already greatly reduced by the time it reaches the muzzle. Most of the pressure occurs inside the chamber and just in front of it. See my current post regarding chamber reducers as much of this is covered. I agree, if the bulge happened midway, it was most likely caused by an obstruction, like maybe a stuck wad.

If I felt I had to alter my shooting style to shoot it, I would not have a minute's peace of mind shooting it. I side with Joe. However, this question came up 5 years ago and opinions were on both sides of the issue to extremes:
http://www.doublegunshop.com/forums/ubbt...&PHPSESSID=

Quite a few brAins got bulged out of shape for sure

Don't know or care what the experts say, but you can be damn sure the bulge isn't stronger than it was before ... not me. Enough crap goes wrong in life without asking for trouble I figure.

Rick

Fluid flow (shot pellets act as at least a semi-fluid) is one of the places where science and "horse sense" part company; one of the reasons it took so long to fly. I know perfectly well that it is easy to see in your mind's eye the shot getting "squeezed" through the choke and that causing higher pressure. If that were true, then airplanes would not fly/venturies would not have lowered pressure in the throat. When a fluid enters a constriction, it must flow faster to maintain mass flow rate. To flow faster, it must "use up" some of its pressure. Otherwise, energy would be created and it isn't. It is well proven that full choke adds at least an average of 40 fps to the shot as compared to cyl choke. That said, pressure is not a reason to change choke.

As for the bulge, if your "slight" is about the same as my "slight", there is only an aesthetic problem. The bulge area has been strained beyond the barrel steel's elastic limit, which translates into work hardened. Odds on, a knowledgable gunsmith can knock the bulge back into place; additional work hardening. Now, another gas hammer (the reason obstructions cause bulges) exactly at the former bulge will have to have higher pressure to rebulge that spot. If the barrel were to be overpressured generally, say by a high pressure shell, the first place to fail (weakest spot) would be at a different spot than the former bulge.

I know the above doesn't meet the "horse sense" test, but is science. I'll be happy to discuss if anyone disagrees or doesn't understand.

Thanks to all for taking the time to reply! Thanks also for the referral to the earlier posts on this subject. Rocketman, Thanks for addressing the question of pressure and choke. Kurt