GrovTec US Inc GTHM320 5/8"-24 TPI .308 Cal Black Nitride Steel Crush Washers (5-Pack)

GrovTec crush washers are a no-nonsense solution for locking down your muzzle devices on .308 caliber rifles. The GTHM320 5/8"-24 TPI crush washer sits between your barrel and muzzle device—whether that's a suppressor, brake, or flash hider—and crushes as you tighten, creating a solid mechanical lock that won't back off during shooting. This 5-pack gives you spares for your arsenal or lets you outfit multiple rifles without hunting down washers one at a time.

The black nitride steel construction is built to handle repeated use. Nitride plating resists corrosion and wear, so these washers hold up whether you're shooting suppressed in wet conditions or running unsuppressed in the desert. The 5/8"-24 thread pitch is the standard for most modern .308 platform muzzle devices, making this a practical accessory for anyone running AR-10s, bolt guns, or other .308 rifles with standard threading.

Install one washer per rifle—drop it on the barrel threads before your muzzle device, then tighten to spec. As the device tightens, the crush washer deforms slightly, locking everything in place. It's a proven approach used by shooters doing everything from long-range precision work to suppressed hunting. Keep a spare pack in your cleaning kit or range bag.

Key Features

• 5/8"-24 TPI thread pitch for .308 caliber barrels
• Black nitride steel for corrosion resistance and durability
• Five-pack for multiple rifles or spares
• Mechanical crush-lock design prevents muzzle device rotation or loosening

Specifications

Frequently Asked Questions

Will these crush washers work with my .308 suppressor or muzzle brake?

Yes, if your .308 muzzle device is threaded 5/8"-24 TPI. This is the standard thread pitch for most modern .308 suppressors, brakes, and flash hiders. Check your device's spec sheet to confirm thread pitch and size before ordering.

What's the difference between crush washers and other muzzle device retention methods?

Crush washers use mechanical deformation to lock the muzzle device in place as you tighten—a simple, proven method that requires no special tools or training. They're one-time-use per installation, so the 5-pack gives you options if you swap devices or outfit multiple guns.

Do I need a crush washer every time I install a muzzle device?

Yes. The crush washer is designed to deform once during installation to create the lock. If you uninstall and reinstall your device, you should use a fresh washer from the pack.

Will these work on my AR-10 or bolt-action .308?

If your barrel is threaded 5/8"-24 TPI, yes. This is standard for most AR-10 uppers and many modern bolt-action .308 rifles. Always verify your barrel's thread pitch and size before purchase.