It is impossible to stop recoil.
Give it a good cleaning, check the recoil spring.
Browning did not invent the 7mm
There are several 7mm cartridges out there.. the basic 7x57 will have less recoil than the .30-06, but there are cartridges marketed as 7mm which produce significantly more recoil.
You will have to call Browning with the serial number.
You can never stop recoil. You can reduce the felt effects, but, the recoil will still be there.
Browning does not make a M70 semi auto 7mm nag
1966.
A call to Browning for a manual or a trip to a gunsmith is in order.
Best left to a gunsmith.
Factory or aftermarket?
try replacing the but pad with a limbsaver and/or change the stock to a heaver one
I believe it was from 1962 onward.