Indeed I have; many times. I have never had a crossbolt fail to close properly. Dust, grime, seeds, etc, will most definitely find their way into the underbites as well. Both are very simple to clean out. Simply break the barrels open and clear the debris. They must be fitted with exact tolerances or they do not work properly as designed. A loosely fitted Greener Crossbolt is asking for problems. In the same manner, a loosely fitted Purdey underbite is asking for trouble. If either one is filled with grime, neither will close properly. Any space in the crossbolt will allow the barrel lug to slap against the crossbolt and, over time, will add to the looseness of the gun.

Yes, I would definitely stake my life around the soundness of a properly built rifle with a Greener Crossbolt or a Westley Richards Doll's head. In fact, I would feel even more secure and have more peace of mind knowing that my gun or rifle is fitted with one.

Anyway, that's my opinion and biases toward over-engineered systems and thus my preferences for a lot of the Teutonic guns today.

I guess we got a little off topic since this started out withe the .303 rifle project