The R-15 uses SAAMI .223 Remington chambers and is not recommended for use with 5.56 ammo. Stick with commercial .223 and you'll be fine.
Only .223 ammo. There are different bullet weights.
No. If it does not have 5.56 on the barrel then use .223 ammo.
>.223
No. Dimension-wise, they are similar, but there are differences in neck angles and case thickness. .223 Remington ammo can be fired in a 5.56 chamber, but 5.56 ammo should never be fired through a .223 Remington chamber.
yes. the 5.56 is the 223 caliber ammo.
NO the .223 is a totaly diffrent round than the .223 WSSM
No
.223 Remington ammo can be safely cycled through a 5.56x45 chamber - 5.56x45 ammo should not be cycled through a .223 Remington chamber. Both types may be cycled through a .223 Wylde chamber, but .223 Wylde may only be cycled through a .223 Wylde chamber.
you can fire both 5.56 and .223 ammo in a rifle chambered in 5.56...but not the other way around! In a rifle marked .223, you should fire .223 ammo only
The max range for .223 is about 300 yards.
No. They're dimensionally similar, but vary in several aspects, and may not always be interchangeable. Generally speaking, most 5.56 chambers will do just fine firing .223 ammo, but it's not recommended to use 5.56 ammo in a .223 chamber. The one exception to this would be the 80 grain .223 Wylde - a round which specifically requires a .223 Wylde chamber.