Joseph: You have a Fucile Modelo 1891 Rifle (commonly called the Carcano) designed by Salvator Carcano and adopted as Italy's standard rifle in 1892. Your specimen was made before 1922, however, there are no records to give a more exact date.

1. Carcano Serial Number Database
2. Terni Carcano Rifle Serial Numbers
3. Terni Rifle Serial Number Identification

The AO marking is likely an inspector or assembly marking.

Gardone Val Trompia; Pietro Lorenzotti; Metallurgica Bresciana; R.E.Terni. To 1945, fixed sight, after 43 this gun had no markings other than serial number.

Your rifle Is chambered for the 6.5 X 52 mm Carcano cartridge which is both difficult to find and somewhat pricey.

To return this rifle to original condition, from what I can see, you need a complete stock, upper and lower handguards, upper and lower barrel bands, rear sling swivel and cleaning rod.

Carcano Serial Number Database

You should consider the cost of restoring this rifle. In its present condition, your rifle is worth $50-$100. The cost of the stock and other parts will likely meet or exceed the value of the rifle. When you restore this rifle, the value will be $150-$225.

From a cost effectiveness standpoint, if you desire a Model 1891 Carcano rifle, they are available at the various internet auction and sales sites for the value of the restored rifle and you will not have the time involved in finding the parts and installing them.

Terni Carcano Rifle Serial Numbers

Original parts are occasionally available on ebay, www.gunbroker.com and www.gunauction.com.

Terni Rifle Serial Number Identification

Also google SARCO and Carcano parts.