Bolt for different receivers

I have an older model 12 with the flat rear receiver that I need a complete bolt for and was wondering if a bolt for one of the newer round receivers would work or if there is anything that would have to be changed out. I see MidwayUSA has them for sale for the round receivers and make mention of the collar. Any help would be appreciated.

Thanks

Jaye

It has been my experience that they are interchangable. The control round feed may neeed to have the ejector removed if you replace it with a push feed.

Thanks for the info