There is no "Remington USA 1906" rifle although there is the Remington Model 8, which was introduced in 1906. This is a semi automatic rifle that was chambered for one of four possible calibers; .25 Remington, .30 Remington, .32 Remington, or .35 Remington. The caliber that your rifle is chambered for should be stamped on the side of the barrel, just forward of the receiver.
No
No.
Only what it is chambered for.
NO!!
a gunsmith needs to check both the ammo and rifle.
yes. the 5.56 is the 223 caliber ammo.
I have had good success with Federal rifle ammo.
No, the 22 Mag will not fit.
Yes.
ABOUT 200 yards, depending on rifle, ammo, and what you call accurately.
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
If your Iver Johnson is marked for the .22 WMR.then yes,if it is not then do not attempt to load or shoot .22magnum ammo in your rifle.