22 lr
7.62x63, otherwise known as the US .30-06.
The caliber is .68, probably the most common caliber for paintballs.
The most common hand-gun caliber used to be 9mm Luger. Recently I bought a pistol and took a self-defense course. Now it seems the most popular caliber is the.40 Caliber Smith and Wesson.********There are popular, and there are most common. The most common gun caliber is .22 rimfire, in terms of the total number sold.
Rifles are mostly 5.56 and handguns are 9mm. There are other calibers that are used, but those are the most common.
Guns are the most common murder weapon in the United States. Handguns of 22 caliber and 38 caliber are most used.
.69 caliber Springfield
Not in the current U.S. military. the most common handgun caliber currently is the 9mm.
Winchester 94 in 30-30 caliber.
I would say it was the Colt revolver. This pistol was produced in various models, calibers and styles. The US Government placed orders for them and many more were bought by private money. The two common model was the Colt Navy in .36 caliber and the Colt Army in .44 caliber.
.223
Winchester 94 in 30-30 caliber.
The most common in the U.S. I believe is the Glock 23, but Sigs, and other models are common also.