A tip I received from a local gun dealer a few days ago about testing the strength of the hammer spring. Place a coin weighing about 10 grams (Aussie dollar is 9g) over the firing pin hole with the barrels removed and pull the trigger. Ideally, the coin should rise about 1.5 metres up in the air if the spring is working properly. I tried this test with my Beretta 682 O/U and the coin went about 2 metres up. Yet to test my Boswell, but will soon.