SGLover;
I realize there are many differences of opinion on a lot of things, but personally I do not consider the lock-up on either an L C Smith or the Lefever as "Weak". It is true that each has only one bolt, but that bolt is situated as far as possible from the hinge taking advantage of the extra leverage & quite obviously has proven to be entirely adequate on both. If you do a smoke test on the fit of guns with all those multiple bolts you might be surprised at just how many actually fit & thus provide anything at all useful to the bolting. This will be especially true om anything other than a very expensive & well fitted gun.
The vast majority of US made double rely on only a single bolt to hold the barrels closed. In the US many, many more guns were sold to "Commoners" than in the UK. The US makers "I Think" wisely concentrated on a single adequate bolt to keep the thing shut & did so with great success.
It is also noted that .22rf & many low intensity handgun cartridges in semi-auto form all operate on the "Blow-Back" principal, IE an unlocked bolt is blown back out of the chamber by the cartridges back thrust. As the cartridge's intensity increased it became necessary to go to a locked breech design. One old Spanish design by Astra did use a blow back design for the 9mm Largo & a few in 9mm Parabelum by the use of an extremely heavy bolt to slow down the back thrust simply by its inertia. This is also the principal by which the famous "Tommy Gun" operates chamber for the .45 ACP round. I "Very Seriously" doubt that an ordinary shotshell case has enough Grip on the chamber walls to make them a single unit as such.
