Regarding chokes
Ive read that the Skeet-res were choked O / C, Open / Choke.
A 75 % pattern at 20 yards left barrel / 75% pattern at 30 yards right barrel.
Skeet in / Skeet out.

I also read that some guns were reverse bored,
Loose on the left and tight on the right.

Can anyone with tools and a .410 Skeet-er give decimal constrictions?

Thanks.