Thread Protector fits AR308 HBAR Contour 5/8 x 24 Stainless- Protect and beautify your HBAR muzzle threads with this beautiful knurled stainless thread protector. Standard 5/8 x 24 thread with a length of 5/8th inch and .740" diameter, it fits all EABCO and Shaw 5/8 x 24 threaded HBAR barrels perfectly. (This thread protector also fits our EABCO 24" 6mm ARC barrel).