Howdy
First off, all Italian firearms are proofed in government run proof houses, to European pressure standards, which are actually slightly more stringent than American standards. ANY Italian revolver chambered for 45 Colt and imported into this country will be safe to shoot with SAAMI Max loads. For 45 Colt that is 14,000 PSI (not CUP).
Look it up:
http://www.saami.org/
That should settle the OP's question.
Second: Safety of any particular ammunition in any firearm depends on
PRESSURE, not bullet weight and velocity. That is why SAAMI lists pressure as the governing factor. Not velocity and bullet weight. Velocity and bullet weight is not a definitive way to define the pressure achieved by any particular load. Two loads using the same bullet pushed to the same velocity by different powders may exhibit significantly different pressures.
Third: There is no official standard for Cowboy ammunition. Some manufacturers define it by bullet weight and velocity, but there is no official SAAMI standards regarding Cowboy Ammunition. It is what ever the particular manufacturer chooses. Yes, they are usually lower velocity loads designed to generate less recoil than standard loads for quicker repeat shots.
Fourth: It is actually very easy to define Cowboy guns. Here is what the Single Action Shooting Society has to say about it:
"REVOLVER REQUIREMENTS
Original single action revolvers manufactured prior to 1899, their approved replicas, and the SASS approved single action adjustable sight
revolvers are the only revolvers approved for use in SASS main match competition. The rules relative to SASS approved revolvers depend upon
the competition category in which one participates. Sights are a major factor for determining in which category a revolver may be used. Certain shooting categories require a specific type of revolver and ammunition be used. Please see the shooting categories for further information. No more than two main match revolvers may be carried to the firing line.
REVOLVER CALIBERS
• Must be centerfire calibers of at least .32 caliber and no larger than .45 caliber or percussion calibers of at least .36 caliber and no larger than .45 caliber.
• Must be in a caliber commonly available in revolvers. Examples include, but are not limited to, .32-20, .32 Magnum, .357 Magnum, .38 Special, .44 Magnum, .44-40, and .45 Colt.
• Standard velocity .22 caliber rimfire ammunition is allowed within the Buckaroo Category only.
• Although the .32 caliber revolvers and .36 caliber cap and ball revolvers are legal, they may not be powerful enough to handle all reactive targets."
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Notice that no specific revolvers are named. Instead, the features of the guns are defined. So an antique Colt, a modern replica, and a Ruger are all SASS Legal 'cowboy guns'. Cowboy ammunition is designed to be safe to shoot in the lowest common denominator, the antique Colt and the modern replica.
