First, an apology. A corrected photo has been posted.

Using a Starrett depth micrometer, I got new measurements.

To the nearest 0.001, my two Marlins are 0.130 deep. My Savage is 0.115 deep.

I need to retire my old dial caliper. When the depth micrometer is set at 0.130, the caliper measures it at 0.140.

Safety on these barrel swaps is easy to check.

Before interchanging barrels, people need to measure cartridge protrusion from the chamber. That measurement must be greater than the bolt face depth.

Bruce