Anyone know what the twist rate is on a factory 550 American 9.3x62 1/14?

1:9.5" TWIST
Yes CZ did a very good thing there.
I own a CZ 550 Medium FS Lux model, and I have checked the twist. That is correct.
The American is the same twist.

My first 3-shots using factory ammo gave .390" at 50 yards to get on paper.
Then I adjusted the scope and moved out to 100 yards, and the 3-shot group there was .306" due to more concentration on my part.

That was with Norma factory-loaded 232-grain Vulcan softpoint.

Even the short bullets work well in that twist inside of 500 yards.

Any bullet you want should work well in the CZ 9.3x62mm.

My 550FS 9.3X62 has a 1:14" twist not the 1:9.5" as advertised. The rifle shoots great so there is no problem as far as I'm concerned.

Well, the plot thickens.
Your CZ 9.3x62mm may have either a 9.5" or 14" twist.
CZ advertised 1:9.5" twist and still do in their 2008 catalog, there in black and white.

They apparently have made some with 14" twist also.

Gotta check your own.

BTW the official CIP spec for "9.3x62" is:

1:360mm

or

1:14.17" TWIST

about

1:14"