Thread: .223 Rem and 5.56mm x 45

Ok so have the new Howa 1500 chambered in .223 Rem, question is....... can I use 5.56mm x 45 NATO in it? Was looking on Wikipedia earlier and they reckoned while you can use a .223 Rem cartridge in a firearm chambered in 5.56 NATO that it wouldn't be recomended to use 5.56 NATO in a firearm chambered in .223 Rem as the load would be too hot and create too much pressure............
Whats the go here?
Is it safe or not?
Appreciate your help
Matt