Percussion Load

[iloco]

I bought a Double barrel percussion shotgun in 12 gauge.  It has Damascus barrels Which seem to be in great shape.
  How much powder and shot make for a safe load...

[Daryl]

3 drams (82gr.) and 1 1/8oz. is a typical load for 12 bore.
The nipples might need replacing. Oft times with percussion doubles, the small hole (restriction) in the nipple
can be at the top., which is not the best position for it as that increases the blow-back pressure on the hammers.
Some had no restriction, which is even worse.
It would be best to have it checked out by a good black powder gun-maker or smith before you shoot it.

[D. Taylor Sapergia]

I have a 12 gauge double with twist steel barrels too.  I load 65 - 75 gr. Fg GOEX, appropriate wads, 1 - 1 1/8 oz shot, without any concerns.  I haven't seen your barrels, so I cannot say that this load will be ok for your gun, and take no responsibility whatsoever for what you choose to load and shoot.  Avoid thinking of your old shotgun as a 3" magnum, and you should be ok.

[iloco]

Thanks Guys.  The shotgun has new nipples.  I will take it to a friend who shoots these types of shotguns.  I wanted one to go with my black powder collection of guns.  I have a 20 gauge smooth bore that I bought from Mike Brooks a few yrs back.

[smylee grouch]

Many many years ago a guy from South Dakota told me a 2 to 2 1/4 dram load was what he would use in a twist barrel I had inquired about.

[Bob Roller]

Close examination before firing is a MUST.I saw one when I was a teenager that was corroded  (apparently)and the gun was blown apart at the breech.Over the decades since I have often thought that "white powder"from a modern cartridge was a factor because I was told by know nothing people it was OK to do that and even at age 14,I knew better.
Bob Roller

[Daryl]

At 27.3gr. per dram, 2 = 54.6gr.
2 1/2 is 68.3.

I would suggest that 2 1/2 is a start with 1 ounce to 1 1/8oz.
 I have used 2 3/4 drams, at 75.0gr. to good effect with up to 1 1/4ounce in a suppository SxS with damascus bls. A London Gun.

[bob in the woods]

You say that new nipples are installed, but make sure the threads on the gun are solid. I've seen a few nipples blown out in my time

[Pukka Bundook]

Daryl's last load mentioned above has worked well for me in a 12 to 14 bore.   
As long as gun is in good order it should work for you too.