AR15.COM had an interesting and lengthy article titled
The AR15.com Ammo-Oracle
Everything you ever wanted to know about .223 and 5.56
ammunition or double your money back.*
They discussed the ammo and the differences in chambers cut for .223 or 5.56 too.
I would also be very interested in how your mini-14 shoots so don't forget to put out a range report after you shoot it.