Depending on condition and originality (no modifications) and assuming the rifle is a 6.5mm Carcano, about $150.
You MAY be describing a Carcano military rifle. If so, values about $150, depending on condition.
The 6.5 Carcano rifle marked "1939-XVII Beretta Gardone A 3739" is a Model 1938 Carcano, which was adopted by the Italian military in the late 1930s. This variant features a bolt-action design and was chambered for the 6.5x52mm Carcano cartridge. The "XVII" designation indicates it was manufactured in 1939, while the "A 3739" likely refers to its serial number. The Model 1938 was used primarily during World War II by Italian forces.
Check the receiver and barrel
Your rifle is likely chambered in 6.5x52 Carcano. This can be veried by a gunsmith.
Unfortunately, we have no idea what rifle you have. Gardone Val Trompia is a town in Italy. It is not a make/ model of a gun. It is possible that you have a 6.5mm Carcano rifle made by Beretta, but without seeing it or knowing the markings, that cannot be determined. As a military rifle, there is no "owner's manual". However, there is information on loading and firing the 6.5 Carcano available. To use as a repeating rifle, there is a stripper clip that must be used to hold the cartridges.
No published sn data. 10-200 USD
$125
Commonly called the Carcano, this was a bolt action military rifle that fired a 6.5mm bullet. It was the standard rifle of the Italian military for many years. It was also the type of rifle reportedly used to kill President John Kennedy.
The standard issue rifle of the Italian military is the Beretta ARX160, which has been in service since 2008. It is a modular, lightweight assault rifle that can be configured for various roles and is chambered in 5.56×45mm NATO. The ARX160 features a gas-operated, rotating bolt mechanism and is designed for versatility and ease of use in various combat situations. Additionally, it has been adopted for use by various military and law enforcement units in Italy and beyond.
You don't give us a lot to work on- but Gardone Val Trompia was, and is, the home of Beretta. Among other firearms, they made different versions of the Italian Army rifle, the 6.5mm Carcano. Value of ANY firearm is dependent on the specific model, and condition. The Carcanos are not especially high dollar collector's guns, and may sell for $100-200. Visit the website for surplusrifle.com for some more information, and see if yours looks like the ones there. As a side note, the 6.5mm Carcano was the rifle reportedly used to assassinate Pres, John Kennedy.
Beretta
Well, we CAN tell you that it is Italian, and lkely a military rifle- since Terni was the national Armory for Italy. Beyond that, we need some description.