For a 300 Blackout setup with 5/8×24 muzzle threads, the listed products are installation accessories—not muzzle brakes. The PLASMAGAL shim kit offers adjustable spacing, while the Ficero crush washers are a simpler one-time installation option. The two thread protectors cover exposed threads when a muzzle device is not installed. No actual muzzle brake was included in the supplied product list, so confirm your barrel and device specifications before buying.
| Product | Best For | Type |
|---|---|---|
| PLASMAGAL Shim Kit | Adjustable positioning | Stainless shims |
| Ficero Crush Washer | Basic device installation | Steel crush washer |
| Down Range 5/8-Inch Protector | Short thread coverage | Thread protector |
| Generic .750-Inch Protector | Longer thread coverage | Thread protector |
PLASMAGAL 5/8×24 Stainless Shim Kit
This kit is best for a buyer who needs to adjust the seating position of a compatible muzzle brake or flash hider. It includes 20 stainless-steel shims in five thicknesses: 0.004, 0.008, 0.012, 0.020, and 0.040 inches, with four of each size. Multiple shims can be combined to reach a needed stack height.
The product is listed for 5/8×24 threads, also written as 5/8-24. Its reusable stainless-steel construction is intended to resist deformation, making this a more adjustable option than a crush washer. Choose it when fine positioning matters. A shim kit is not a muzzle brake, and selecting the right stack and installation method requires following the muzzle-device and firearm manufacturers’ instructions.
Ficero 5/8×24 Steel Crush Washers
These Ficero washers are best for buyers seeking a straightforward washer option for a compatible 5/8×24 muzzle device. The listing describes CNC-machined steel with a black oxide finish and includes 12 washers. The product is also described as being for .308, but buyers should verify thread and shoulder requirements for their specific 300 Blackout barrel and muzzle device.
Compared with the PLASMAGAL shim kit, a crush washer is the simpler choice when fine, reusable thickness adjustments are not the priority. The listing does not provide washer dimensions or explain whether the washers are reusable. Do not assume they can be reused; follow the device maker’s installation directions.
Down Range 5/8-Inch Bull Barrel Protector
This thread protector is best for someone who wants to cover unused 5/8×24 barrel threads rather than attach a muzzle brake. The listing describes a stainless protector for .308 and 7.62 bull barrels, with a length of 5/8 inch and a diameter of .930 inch. Its stated dimensions help buyers compare it with the longer protector below.
Choose this model if its listed length and diameter suit the barrel’s profile. The supplied product details do not specify additional fit measurements or confirm compatibility with every 300 Blackout barrel. Check the barrel’s thread pitch, shoulder, and available clearance before ordering.
Generic .750-Inch Bull Barrel Protector
This option is best for buyers comparing a longer thread protector for a bull barrel. The listing identifies it as a 5/8×24 protector for .308 and 7.62, with a .750-inch length and .930-inch diameter. It is not a muzzle brake; its purpose is to cover exposed muzzle threads when a compatible muzzle device is not fitted.
Compared with the Down Range model, this protector is 1/8 inch longer according to the listed lengths. Choose it if that added length fits your setup. The product details do not state its material, so do not assume it is stainless steel based on the other listing.
Buying Guide: Choosing 5/8×24 Parts For 300 Blackout
Do you need a muzzle brake or an accessory?
A muzzle brake is a muzzle device intended to redirect escaping gases. Shims and crush washers are installation components, while thread protectors cover exposed threads. The four supplied listings include no brake. If your goal is to buy a brake, look for a product explicitly identified as a 5/8×24 muzzle brake and verify its bore and firearm compatibility before purchase.
Should you choose shims or a crush washer?
Choose shims when adjustable spacing is useful: the PLASMAGAL kit provides five thicknesses and is described as reusable. Choose the Ficero washers if you want a steel crush-washer pack and do not need the listed variety of shim thicknesses. The provided details do not establish that the crush washers are reusable.
What should you check before ordering?
- Confirm that the barrel has 5/8×24 threads; a similar-looking thread size is not sufficient.
- Check the muzzle device maker’s requirements for washers, shims, and installation.
- For a thread protector, compare its listed length and diameter with the barrel and surrounding components.
- Do not treat .308 or 7.62 wording alone as proof that a product fits every 300 Blackout setup.
Threaded muzzle-device installation can affect firearm safety and alignment. If you are unsure about fit or installation, consult a qualified gunsmith and the firearm and device manufacturers’ instructions.
Frequently Asked Questions
Are any of these products 300 Blackout muzzle brakes?
No. The supplied products are a shim kit, crush washers, and thread protectors. None is listed as a muzzle brake.
What does 5/8×24 mean?
It describes a thread size and pitch. Verify that your barrel and chosen accessory both specify 5/8×24 before buying.
Are shims and crush washers interchangeable?
They are different types of installation components. The shim kit offers multiple thicknesses; the Ficero listing describes steel crush washers. Follow the muzzle-device manufacturer’s specified installation method.
Which thread protector is longer?
The Generic protector is listed as .750 inch long; the Down Range protector is listed as 5/8 inch long. Both are listed with a .930-inch diameter.
Can I use a thread protector instead of a muzzle brake?
A thread protector covers exposed threads but is not a brake. It does not serve the same function as a muzzle device.