Pachmayr Decelerator
Most folks find the LOP is too long with hunting coats for waterfowl ,which will affect gun fit and which of course causes more felt recoil.
So...
Gunsmith fits gun to shooter , with shooter wearing hunting coats, shortens LOP and sticks on a Pachmayr Decelerator.
Then...
Since most waterfowlers shoot from positions other than standing - the shooter gets hung up on mounting gun to face with coats and and again more felt recoil.
So...
Inside of pad, toe and heel of gun are contoured to assist in correctly mounting gun to face.
Plus...adding a pad to comb. Pach makes one, one can use Moleskin, or make one from a mousepad.
Comb fit is part of gun fit earlier...however...improper form caused by being in a more restrictive shooting position, a shooter will get a bad mount, trip trigger on a roman candle and them things flat hurt, especially when its cold out.
So a pad might be part of gun fit, or one can be added if need to assist.
The thickeness can be tweaked as need as well.
Then again I cheat, I use 2 3/4" shells from a 835 and let the Greenheads come on in a bit.
The two or three 3.5" shells my buddy and I have in a pocket is just to have.
I / we back up folks so sometimes, we shoot more than some folks do
"Whoa! You guys ain't sore from shooting them roman candles?"
"Nope!"