The purpose of a denent is not to stop balls from roling out of the barrel, but to stop double feeding. In Open bolt guns it serves to stop the ball from double feeding, but in doing that it does not role out of the barrel.
The cocker is closed bolt, and it has a denent, but this denent does not stop if from roling out of the barrel. It is positioned back so that if you were to holt the trigger back, keeping the bolt back, you would not have ball after ball roling into the breach. Once the ball is chambered it is free to role if te paint is small.
This is the same with the excalibure, but in the excal, the denent really serves NO purpose because it's electro.
The Old shocker is another closed bolt gun with no denent, and it works just fine, I never had a double feed with it.
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