I'd suggest asking John Schubert, Schubert's Gun Shop in Lynchburg, 434-851-6044 (cell) jschuber1@adelphia.net to take a look at the gun. There are several LCSCA members from VA who might have other names. No way to know how big a problem this is without checking the head of the stock, and reassembly of LCs is tough. Done right, you should be confident in using any 7/8 oz 20g load IF the chamber is 2 3/4". And BTW: shooting 2 3/4" shells in a 2 1/2" chambered 20g can significantly increase recoil and may have caused the crack. I recently had a smith glasbed the head of the stock and repair some cracks in a 16g for $150. Please let us know how things work out for you.