In today’s industry, there are 3 main ways to install a muzzle device on the dime a dozen AR15 or any threaded barrel on the market. You have the crush washer, the shims and them you can pin and weld the device. But for the sake of time I will only talk about the crush washer, and the shims.
Most muzzle devices on the market need to be timed, meaning for it to do its job correctly, it must be positioned in a certain way. Many companies will included a set of metal shims, such as PWS with their muzzle devices. Now I will say that the choice of installing the muzzle device is 100% personal, and each of them work, and each has their pros and cons.
Now, for me, I prefer the crush washer, as it is very simple install and takes less time than the shims. Simply slide the crush washer on, thread on the device until it is too tough to twist by hand, then turn the device with a wrench until it is timed properly, simple as that. The other pro to the crush was is that it has constant pressure on the device to keep it from getting loose. The only con that I have ever found is that they are a one time use item, but you can buy a 10 pack for a couple bucks, or do what I do and buy a pack of crush washers from Honda, that are about 20 to a pack for a couple bucks, just need to use a sharpie to make them black.
When it comes to shims, I find these useful for really getting the timing spot on with the muzzle device, when you are an anal person and have CDO, which is OCD but in the correct order. The down sides to the shims is that many of times I have seen the muzzle devices to come loose, and come out of timing. It can also take 3 times longer to install the muzzle device as you have to constantly thread on, and thread off the muzzle device till the timing is correct. The last down side is that most shims are company specific, and cannot be used with other muzzle devices. Yet, most muzzle devices will take the standard crush washer.
The choice is yours, and hopefully this gave you a quick insight on the options to use when installing muzzle devices, or this took up time while you sat on the porcelain throne.
feature photo courtesy of surplusammo.com