A100 upper on a Mark 2 lower with a Mark 2 bolt.

[CHEVYINLINE6]

I have read you can take a A100 upper and stick it on a Mark 2 lower and using a Mark 2 bolt to have a bolt hold open feature like a Mark 2. You probably could use a Mark 1, 3 or 4 bolt also. I only have two Mark 2 pistols at the moment, but several Standards and a Mark 1. I got spare parts and want to build another Mark 2. I am keeping my eye out for a Mark 3 lower so I can build a Mark 2 with a magazine drop feature like a Mark 4. I scan the internet everyday looking for new and used affordable spare parts to buy.

 

[TestEngineer]

There are subtle differences between uppers, lowers, bolts, and internals that usually prevent drop-in swapping. Some modification and fitting is usually required, and there's limits to what will work with what.

The easiest way to get the last shot hold open with your Standards and Mark 1 is to make taller followers for your magazines. The followers then stop the bolt after the last shot.

 

[Dan in MI]

The parts swap very readily across the std, I, II, III frames. There are small details but usually no big deal.

I've got at least a 1/2 dozen completed FrankenRugers and another four or five in process.

Parts are no longer cheap. With the flood of Volquartsen take off uppers at $35 anything lower related has gone through the roof.

Check out Wirthwein Guns for a ton of information on what you are looking to do as well as parts.

 

[1gunsnotenough]

I have read you can take a A100 upper and stick it on a Mark 2 lower and using a Mark 2 bolt to have a bolt hold open feature like a Mark 2. You probably could use a Mark 1, 3 or 4 bolt also. I only have two Mark 2 pistols at the moment, but several Standards and a Mark 1. I got spare parts and want to build another Mark 2. I am keeping my eye out for a Mark 3 lower so I can build a Mark 2 with a magazine drop feature like a Mark 4. I scan the internet everyday looking for new and used affordable spare parts to buy.

Pretty much all M1,2 and 3 parts interchange.