redoing the flash pan

[yip]

   i have a pedersoli brown bess, and flash pan has a groove cut in it where it contacts the barrel, from gas and heat when fired. how can i fix this? i guess the flash hole is a little low causing this. i'm just a little afraid of a potentional bomb in the lock mortice. any help?

[The other DWS]

This is just my relatively uninformed guess but to me it sounds like the Pedersoli mystery-alloy pan is too soft to resist the eroding jet of hot gas and particles blowing out the touch hole and the touch-hole is so low its catching the edge of the pan floor. I think the jet is supposed to blow the length of the pan and then be deflected up and out by the contour of the outer end of the pan

Perhaps if the pan was ground deeper and hardened, and/or if the touchhole was drilled tapped and an properly plugged and a new one or a liner installed to move the touchhole up a bit

[Habu]

How much has the gun been shot?  It sounds like you are eroding the pan--I had a couple guys say I was crazy the first time I had this happen with my old Bess. 

You can install a liner and move the touchhole up, but you may not need to.  Where is the touchhole in relation to the bottom of the pan/top of the pan?  You could also have an oversized touchhole (I noticed when I enlarged the diameter of the touchhole, I tended to get more gas erosion in the pan). 

If the gas cutting annoys you, you can always clean it up and braze the pan bottom, then grind/file/scrape it back to shape.

Pictures?

[FALout]

You mention "bomb" in the lock mortice, is there a gap where the lock is supposed to be touching the barrel?  If not, nothing to really be worried about, if it's cosmetic, then you can do as suggested. If there is a gap that is allowing powder to get into the lock mortise, then you should do something about that like inletting the lock in further or soldering on a shim to fill the gap.

[Roger Fisher]

The jet cutting the bottom of the pan 'may' very well be cured by reshaping the inside bottom of the pan lower should have plenty of metal there to do so.  Heck it can't hurt and may be the answer.  I must admit all I've done in that vein is to widen the pan to catch more of those sparks we need to set her 'off'

[Acer Saccharum]

You can also fit up a leather gasket between barrel and lock. Is this a dumb idea?

Or TIG weld up the lock bolster face, and flatten it out again.

Or, as someone said, file it flat, and inlet the lock deeper. But watch how far you can go in without making matters worse, cosmetically and mechanically.

[msw]

if the flash hole is too low, you may want to consider a new touch hole liner.  i'm partial to the White Lightnin' liners, but there are a bunch of good ones on the market.

if there is a gap between the edge of the pan and the barrel (i.e. if the pan doesn't fit snug against the side of the barrel) then you have a place for priming powder to sneak into the lock mortise, where bad things can (and eventually will) happen.  to prevent this, i would recommend that you put something in the gap.  i've used a bit of brass shim material which i silver soldered onto the lock, and i've had good success with this, but i do keep an eye out for this piece falling off and if it were to do so, i wouldn't shoot the rifle until it was repaired.

the shallow groove will stop growing if you move the location of the touch hole (at least, that's the theory).  to fill this in sounds like a welding problem, and i would defer to those who know about welding on that issue.

good luck with your Bess.  once you get them going, they're a lot of fun to shoot!