Perazzis can be anything from 18.4mm (.724") to 18.8mm (.740"). There is no "standard" bore dimension. Different dims for different guns and configurations, whether or not it has screw-ins or fixed chokes, etc..

My old Winchester imported MX-8, with 31 1/2" barrels and fixed chokes, measures .727" bottom and .725" top. Most that are imported into America have bores from .736" to .740", and the European models are tighter, as I understand it.

SRH

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