yes. the 5.56 is the 223 caliber ammo.
Yes but I would only shoot those loads with a 55gr.bullet or lighter.I believe the smith and Wesson model 1500 has a twist rate that is not made for the heavier bullets found in todays .223 ammo.
Yes.
No
No.
Only what it is chambered for.
You will have to shoot as many different brands and bullet weights as you can find/afford. The rifle will exhibit a preference for one or two.
The US model 1898 Krag Jorgenson rifle was chambered for the 30-40 krag cartridge.These are still loaded by remington arms company.
NO!!
I'd stay with standard velocity ammo which it was designed for.
a gunsmith needs to check both the ammo and rifle.
I have had good success with Federal rifle ammo.
No, the 22 Mag will not fit.