223 55g vs 72g, which will give heavier felt recoil?

You need to also state the velocity and incorporate it, and the powder charge and gun weight. Free recoil can be calculated with this neat little program at handloads.com:

http://www.handloads.com/calc/recoil.asp

That will do it. Thanks

Short answer: You can't feel recoil from either one of them.

Now a .375 or .458, those have recoil!