Powder equivalent charts

I have a heap of ap100 here left over from 357 mag
I thought I might use it up in 44/40 (only other pistol round i shoot) but no data
Looking on the adi equivalent chart they say ap100 is equivalent to imr sr4756
Looking at the imr data and they have sr4756 data with the 200gn cast bullet
The exact bullet I use

So could I use a recommended sr4756 starting charge or just under
Of ap100 to get a starting charge

Only intend to load light for cowboy ammo to practice with instead of shooting black powder constantly
Cheers

Nobody got any information?

Talking through my butt, but powder equivalence is not an exact science.

If you then are also "going slightly lower than" the more-or-less equivalent minimal load, then you are deliberately adding an uncertainty level to something also not absolutely certain.

I'd just stick to the minimal equivalent load and not go further down. Someone else please shoot me down to save rambo's fingers.

AP100 is not ideal for .44/40 in a pistol for light loads. It is better suited to magnum type loads. I would recommend getting (trading?) a faster powder like AP70 or similar rate powders from other makers. Lighter charges of the slower powders create unpredictable pressures.

Get some Trail Boss that is designed for Cowboy loads AP100 is not very popular most people skip it and go to 2205 for the higher velocity

Sweet as normally use ap70 just have most of a tin of ap100 here I was going to use up if it was Viable