I can't say for an EM model but my FAIR Iside Tartaruga Gold .410 has five choke tubes that are not at all accurate as to their actual constrictions. Here are the actuals for them.
As marked, and as measured:
Cyl. .006"
IC .003"
Mod. .012"
IM .023"
F .034"
This doesn't take anything away from the usefulness of the gun, because knowing what they actually are and how they pattern lets me choose what I really need. Fact of the matter is, you can't go by the choke markings on much of any choke tubes by any manufacturer. CompNChoke is the exception that I have found. They are very consistent.
Thanks Stan, looks like they got the cylinder and IC ass backwards!
I know you have to pattern the load your using, but the choke construction gets you in the neighborhood
Thanks John for your comments.
Stay well my friends
Greg