Mehul-

My daughter turns four years old next month.
Her favorite rifle (since she was just about a year old) is a full-stock fur trade (replica) light 50 caliber flint rifle that had belonged to my late father.
I haven't built anything specifically for the kids yet.
They're pretty happy with what we have laying around the house most of the time.
I do like the idea of the fifth birthday gift though...

Talk to our friend Mr Zihn and see if he can swing your selection process over to flint and charcoal!

Cheers
Tinker