This Smith Enterprise M14 / M1A Thread Adapter allows the shooter to easily convert their Springfield M1A's muzzle threads over to the more common 5/8"-24 pitch for compatibility with a greater number of flash hiders, muzzle brakes and sound suppressors. The adapter is machined from fatigue proof steel bar stock, and features a rectangular hole for a castle nut (not included). Its dovetail fits any USGI type front sight.