I don't know if my limited experience is going to help any in this thread, but when sighting in Turkey loads in my Remington shotgun, it feels more heavy recoil than when I shoot my Remington 30-06 BDL with a plastic butt pad.
I can shoot that 700 for the entyre afternoon and it don't bother me at all, but 25 rounds with my Remington 700 BDL in 300 W. M. (with recoil pad) and I get a headache from the whiplash.
I will say that Turkey loads feel to me like the 300 Magnun.