Hello Danny, As Doctor Drew pointed out your old L C Smith SXS 10 gauge was most likely built to shoot a 2 and 7/8 inch long cartridge that used LEAD SHOT and nothing but LEAD SHOT...... Do not shoot STEEL shot through your old L C Smith.... As Doctor Drew pointed out you can buy the correct cartridges for your old L C Smith from RST....
http://www.rstshells.com/store/m/1-10-Gauge.aspx ...... Good Shooting To You, Jent