Not sure if this is the right place. I acquired a Holland and Holland double rifle. It is a 500 bore made in 1886. The load is engraved on the action; 5 dram, 3-1/4" with standard bullet. I sent an email to H&H asking what a standard bullet is. Anyone have any information on coming up with a load? I have handloaded for a long time, but having a problem with drams.

I've got no info on which bullet was the "standard" with that rifle.

Try posting in the Express Rifles and Big Bore page.

Congratulations on your H&H double! I'm jealous

I have the same rifle, "Shooting the British Double Rifle" by G. Wright lists on page 272 under Black Powder Express loads:
.500 X 3 1/4 with 142 BP and 440 lead bullets = 1775 f/s.

I shoot LBT 350 with like charge of 4198 to the sights at 50 yards.

My Sunday shooting gang has two more H & H .500 3" BPE doubles that regulate well with 350 or 440 grain bullets.
Go to "Nitro Express.com" under Double rifle archives to see my Holland, Rigby, Woodward, Alex Henrys, and other double rifles and the targets I've shot with them.
I posted as "OahuKaneohe" on that forum.

Get that book by G. Wright and read it.

A dream is 28 grains. 7000 grains per pound.