This is a new shim kit designed for precise alignment of muzzle devices on barrels with a 1/2x28 TPI thread, commonly used for .223 Remington and 5.56 NATO firearms. The set includes multiple shims to help users achieve the correct orientation when installing flash hiders, muzzle brakes, or suppressors. It is a practical solution for gunsmiths, hobbyists, or anyone assembling a custom upper receiver where timing a muzzle device is necessary. The shims allow for minor adjustments to ensure a secure and properly aligned fit. This item ships new and includes free shipping. Always verify compatibility with your specific barrel and device, and consider professional installation if you are unfamiliar with the process. Check the listing for full details on included shim sizes and quantities. Shim Kit for 1/2"x28 Thread Barrel Muzzle Devices Alignment Set .223/5.56 (20. Condition: New, Made in United States. Listed at 21.59 USD. Fit Barrels with 1/2"-28 TPI (.223/5.56) Threads.