Earlier this year, Caveman LLC introduced a series of crush washers for AR-15s that change to bright colors when the barrel starts to heat up past 131 degrees F (55 degrees C). Caveman states that the intended idea behind their Spark AR-15 Crush Washers is to warn shooters when the barrel is too hot to touch or store, and at which point accuracy might start to decline, thus changing from black to one of four bright colors. The new Spark AR-15 Crush Washers are available in white, orange, green, and purple. Caveman LLC’s description can be read below.

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Image credit: Caveman LLC

Introducing the SPARK™

The Spark™ crush washer (1/2″)

• Black to Bright at 131F (55c)
• Know when your barrel is too hot to safely handle or store.
• Color activates at common bullet drift temperatures.
• No more guess work.
• Insanely bright & awesome colors.
• Makes crush washers cool (at least…as cool as possible).

No more stupid:

• Hand hovering
• Barrel tapping
• Spitting (people really do this…stop it)

Note: extended operation over 450ºf can result in breakdown of thermochromic properties.

***Note about Installation***

If more than 180 degrees of tightening is required for timing, please use shim. Over tightening can cause damage to the Spark™ and it’s coating.

Image credit: Caveman LLC

Image credit: Caveman LLC

Caveman’s new Spark AR-15 Crush Washers can be found on their website, CavemanLLC.net, and are listed for $9.99 each. You can follow them on Facebook, Instagram, and YouTube. Caveman LLC also has a similar, toolless concept called the Flare, which are silicone rings that also change color when on a rifle barrel, or pistol suppressors, and can work up to 450 degrees. Caveman states that they’re still working on large caliber suppressor Flare rings.

What do you think about the Spark Crush Washers, are they useful, a nicety, a novelty, or something else?