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.
The recoil of a 7mm rifle cartridge, such as the 7mm Remington Magnum, can vary depending on several factors including the specific load, the weight of the rifle, and the shooter's stance. Generally, the recoil is moderate to heavy, often measured in foot-pounds, and can range from about 15 to 25 foot-pounds. This level of recoil can be manageable for experienced shooters but may be challenging for beginners or those sensitive to recoil. Proper technique and equipment can help mitigate its effects.
You will have to call Browning with the serial number.
Browning does not make a M70 semi auto 7mm nag
1966.
You can never stop recoil. You can reduce the felt effects, but, the recoil will still be there.
A call to Browning for a manual or a trip to a gunsmith is in order.
Best left to a gunsmith.
Factory or aftermarket?
300-800 USD