Probably all of the third type locks are as good as anyone if they are of the type that restrict vertikal and horizontal movement at the same time, but if not fitted properly they are as bad as any one of them.

But on the matter bringing it on face again the dolls type are a bit worse then the crossbolt, what i mean is that when the breech is brought closer to the action you loose the horizontal fit. On the crossbolt its possible ti fit a larger bolt, but then again noone does.

Also if the breech is brought back agains the action you loose the fit on the front part on the lugs of the lump and the bolt has to take the whole blow.

If there is a possibility to sleave the barrels as mention in this thread and fit the sleaves to the action it would solve a lot of trouble, that is if the sleaves at least are as big as the rim.

And for the record, i love the crossbolt, greener or kersten, they are simple and as strong as any of the other.