Every now and then Kent does a run of their Pure Gold line, for the old gun shooters.
P&D in Edmonton had some last time I bought them. They ran about $12 a box.
Saw a pirate trying to get $35 for a box at the Kamloops Gun Show. I passed.
Depending on what you are shooting them in, the standard velocity loads in a 2 3/4 shell may shoot just fine. Check your actual chamber length, and confirm for yourself.
This based upon some info that was published in The Double Gun Journal, where, instead of believing what was the common belief, the guy actually put pressure transducers onto his shotgun barrels and tested them.
Dig around the Doublegunjournal site and you should be able to find the data.
The Army and Navy double (Webley Scott and Sons made, IIRC) has a pretty long chamber and shoots the light target loads just fine.
YMMV
Otherwise it's a reloading gig.
Cheers
Trev