.223/5.56 Military Style Chamber Brush (#8-36 Threads) Designed for AR-15, M-16, and M4 and similar MSR. KleenBore's Military Style chamber brush is designed for heavy use and has the core wire looped through the brass coupling. Threaded #8-36. The KleenBore military style chamber brush is configured with two brush diameters; the first stage of phosphor bronze cleans the chamber area, while the second stage of stainless steel cleans the bolt lock up area. Please note that the #8-36 coupling is not a standard thread size and will not fit most commercial cleaning rods. However, these will fit KleenBore multi-section rifle rods found in the Classic Rifle Kits, Field Pack Kits (Military Style Pouch Kits) #POU301B, #POU302B, #POU302T, and the All Caliber Vinyl Pouch Rod Set. (#S-170) Features: Military Threads #8-36 Brush Core looped through coupling Made in USA