In regards to recoil of big bores, here is an example
of the difference between guns.

Here is a comparison between 4 of the 500 Nitro doubles I own / have owned
which are as follows

1. Army & Navy (Webley action), 27" Barrels, 12lb. 12oz Slightly barrel heavy Thin Stock, Greater drop at comb
2. Army & Navy (Webley action), 27" Barrels, 12lb. 12oz Barrel heavy Thick Stock
3. Westley Richards, 22" Barrels, 11lb 5oz Very well balanced Thick Stock
4. Joseph Lang (Webley action), 27" Barrels, 11lb. 11oz Very well balanced Thin Stock

No 1 which has a thin stock and a Greater drop at comb and as a result
is a bit of a prick to shoot as it is hard to get your cheek down
as the comb is a bit low. As a result it tends to "kick" up a bit.

No 2 with the Thick Stock is an identical rifle to No 1 but is far more pleasant to shoot
with everything else being equal (loads etc). Since No 1 and No 2 are a matched pair in all respects
except the stock, it is a great comparison.

No 3 is great to shoot and very well balanced - it feel like 8lbs in your hands.

No 4, the Joseph Lang felt "heavier" than No 3 even though it is only 6 oz heavier
but being well balanced it just "hangs" there when at the shoulder. However you still
know you are carrying it after a day.

Hope this provides some insights into felt recoil.

500 Nitro