Ernie- What you do is cut off several strands so the wire will fit in the breaker, but do it on the back side so the inspector don't see it. ha ha ha
We call that a 'haircut'.
I have done it several ways,I personally like a good mechanical connection.
Depending on the conductor size I try to use the crimps Reno addressed.
My supplier loans out the crimp tools for no charge,As well as leaving stock behind the shrubs Saturday afternoons!
Thats why I use them!