The manual for a Kodiak indicates that the ramrod dose extend, as does the manual for an Apex. I own a Kodiak, and it does indeed extend. I have had no trouble with mine, but I do think a range rod is a very good investment. I plan to get one when I have some spare funds. It seems that a longer, and stronger rod would help with range shooting and cleaning the gun.
As for the difference between the guns, look up the manuals and see for yourself
Kodiak:
http://www.cva.com/warranty/CVA%20OptimaKoiak%20Warr%20Book.pdf
Apex:
http://www.winchestermuzzleloading.com/docs/Apex.pdf