Pilgrim

Try this,
Seperate the barrels from the stock.
Hold the barrels by the bottom "hooks" letting them hang down.

Careful do not drop them.
With your knuckle or something wood, like a hammer handle gently rap the bbls.

You should hear them "ring".
If they do not "ring" but sound flat, the solder on the bbls/ribs could be loose.

Also are you shooting your rifle at the range off of bags. Try shooting it sitting more upright [pile the bags higher], simulating standing.
Hold the forearm resting, only the back of your hand on the bag just enough to steady you.
Do not use a rear bag.

Let us know what happens.