Flat - round action??'s

[750k2]

Do bolt collars interchange between the two?
Get a complete bolt and just change the collar?
I have a small pin bolt head and the bolt on the rifle has a large pin bolt head.
Are firing pins interchangeable - as in get a new small firing pin to run the small pin bolt head.
And finally are bolt handles the same between the two actions?

[GaCop]

Bolt handles are interchangeable between the actions except for the Axis. I don't think the new FPs will fit the older bolt body but I have no experience with the newer firing pins so someone with more knowledge will no doubt chime in on that. Bolt heads are interchangeable to a point if going from one type action (short to short or long to long action). The cocking cam collar is interchangeable between long and short actions.