Can anyone please advise whether the CZ 527 in .221 Fireball uses the same trigger guard / magazine housing as the .22 Hornet . The Hornet magazine body is 2.265 inches in length .
The .222 and .223 use a slightly longer magazine and different trigger guard .
Wondering whether it is feasible to open up the Hornet boltface / rechamber to .221 and buy a new magazine .

try their contact page-

http://www.cz-usa.com/about_contacts.php

that's email and an 800 number; they get lots of calls and emails, they're good about it. Although it's not the question you're asking, they'll sell you just about any part on the rifle, a bolt, too, I assume. You could end up with the capability of returning the rifle to Hornet in the future.

They've always responded to me cordially and quickly.