Did the 'smith specify whether it was a Belgian "W. Richards" or and English "W. Richards?" There is a lot of difference. Belgian made guns were farmer tools and the English made guns much better, even in lower grades. It is unknown if W(illiam) Richards of Preston/Liverpool was involved in the use of his "W. Richards" brand on the Belgian guns or if the Belgian use of "W. Richards" was purely an attempt to fool Americans into thinking they were buying a Westley Richards (who never used anything but "Westley Richards").
2 1/2" hull length is not the issue for your gun. Low pressure loads that will give it the least strain is the issue. Several of the smaller shell companies are now selling low pressure loads for vintage guns. Many of us who shoot vintage guns reload low pressure, low velocity, and low recoil shells for our guns. BTW, black powder is not the answer as BP loads are basically as high in pressure as nitro.
