My dad bought me a Belgium made Auto 5 when I was 15. 30 some-odd years later after I'd left it at my parent's house after hunting with it all through high school, dropping it in beaver ponds, running countless shells through it I brought it home after my folks passed away. Left it there due to Army career travelling all over. Gave it a good cleaning and my son shot it on the dove field for the first time in a long time. First whitewing rolled up by that old kicking SOB.
setting the friction ring correctly is the secret to lowering the kick... that long-action in mine is a slow ka-thung. mine was built mid-50's best guessing. it even cycles a 7/8 cheap dove load.. have never shot any loads heavier than 1 1/8 a GOOD gunsmith familiar w/their innards can help. your boy should be thrilled