For those building an AR, a specific grease is required to use on the barrel/nut installation. With all the money you have invested in that new build do it right by using the recommended grease. AeroShell 33MS meets that MIL-21164D requirement. Each container has enough grease to assemble several weapons and sells for $3.00 and $3.00 shipping. Add up to 5 containers for a single shipping charge. E-mail me direct at ontgt10@ cox.net for payment and shipping instructions. Tulsa area pickup is OK.