I met a gentleman at the range who created an up scaled Rem 700 type action for a 50 BMG rifle.It was not particularly heavy and it had no brake.
He built it,he had just undergone open heart surgery,and could not shoot it.He invited me to shoot it for him,I was happy to.
It was a big,slow push.Not painful.
The other hard kicking rifle I have fired is a 416 Rem. Pretty serious recoil,but,with the butt placed on my shoulder,it did not hurt...
HOWEVER!!.With even cartridges like the 30-06,if I shoot enough of them,particularly from the bench,the recoil begins to penetrate.
Round one of the 416 did not hurt. But by the time I get to round...12,or 22,or at some point,I'm "tenderized" It starts to hurt.
I've been scope cut by a 7mm rem mag,but that is just my own fault.
For the most part,IMO,if a reasonably well fitted rifle is shouldered correctly,and if I can get a firm hold while relaxing,so I can be like a willow tree rather than an oak, I don't get pain out of a reasonable number of rounds.
I WILL give an "honorable mention" to Crescent buttplates and original sporting Remington Rolling Blockbutt plates!.They amplify things a bit.
I'm not suggesting I'm anything special,I just have not shot "stopping rifles" and I have found if I do my part,its just a ride,for a few shots.
I did bury.
the break-open lever on a 10 ga single barrel in the web of my hand.
Pulling it back out kind of tingled.