My 1851 Navy doesn't allow the cylinder to rotate at half-cock. With the barrel and cylinder removed, the bolt is seen to drop down as the hammer is drawn back from full-forward to half-cock, but then the bolt pops up at half-cock, which locks the cylinder. The gun otherwise operates as it should.
I haven't taken it apart further yet, but is the bolt arm of the spring perhaps not positioned correctly, or bent? Or is there maybe another cause?
