When I was 30 I moved a piano on my own, with some blocks and boards I got it into my house. Last year I tried to get it out of my house .I couldn't manage it . I guess its because I'm nearly 30 years older. The answer to your question ,with out going into reams of discussion about metallurgy ,discussions on weather the gun in question had a forged action the quality of the barrel steel,metal fatigue,build quality etc.etal. Its old and was probably never expected to take heavy loads or to have lasted so long.