Little Crow Gunworks offers it's own line of thread protectors that will prevent damage to the threads of your rifle barrel when a muzzle device is not installed. They are available in Stainless Steel and Black Cerakoted Stainless Steel in a variety of sizes.
Available Sizes:
1/2"-28x.650 x 5/8" long
1/2"-28x.750 x 5/8" long
1/2"-28x.835 x 5/8" long
5/8"-24x.700 x 5/8" long
5/8"-24x.835 x 5/8" long