Joe;
Many guns having only a single bolt, either under or top, did indeed stand the test of time. My personal go-to gun today is a single, top-bolted, Lefever some 110 years old. Neither it the Bakers, Parkers, 21s, LC Smiths, AH Foxes, NIDs etc ceased production because their single bolt was inadequate, but for other reasons. I have nothing against a double bolted gun, in fact own some, But I have no illusions that just putting on two bolts automatically makes it a superior gun or that a gun having but a single bolt is automatically inferior.
I, in fact just went & did a quick scale measurement of bolt distance on one double bolted gun & the Lefever. distance from the C/L of hinge to rear of notch on the double underbolted gun was 7/8" for front bolt & 2" for the rear. For the Lefever top bolt it was 3Ľ". Thus if enough pressure was put upon the bbls in an opening direction to put 100lbs of strain on the front bolt, the rear bolt would only be stressed to about 44lbs, while the Lefever bolt would only be stressed to 27lbs. SO; Yes!! a single well fitted bolt of proper construction is quite adequate for the task. Therefore "IF" the bolting of the Purdey in question is inadequate, it is not because it is a single bolt only, but for the simple reason it was not of adequate build to begin with. Having no experience with this particular model of gun I am unable to actually answer that, but I can definitely affirm there are a good number of single bolted guns which are entirely adequate for their purposes. In fact the Ithaca NID which was the first gu to chamber the 3˝" 10ga magnum was in fact a single bolted gun.
