I want to buy a complete MkIV lower assembly (frame, trigger, internals, etc).

Will other Mk model lower receivers work with a MkIV upper? If so, I will buy one. Are regular MkIV and 22/45 lower receivers interchangeable?

Not sure whether to put this in "Firearms" or 'Parts & Accessories" since the lower receiver isn't the firearm.

Let me know what you have. Thanks!

Orange County, CA