Posted: 1/23/2014 12:20:28 PM EDT
Just picked up a new 6721 and the rifle is really nice. One thing a bit odd is this brown stuff in the barrel extension. I haven't fired the rifle yet. The barrel extension and chamber have been thoroughly cleaned with CLP and a proper chamber brush. It looks like rust, but I don't think it is as it will not come off at all. Any thoughts?
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I've got two Colt 6721 (also two 6920 and a USGI M16A2 Colt upper), one of my old 6721 is a new old stock that was made in 2002 but I bought it in early 2005, those are just dried factory preservative and it will come off by using a strong bore cleaner (I use Shooter's Choice).
CLP are not a very good bore and chamber cleaner, use a specific bore cleaning solvent which are stronger cleaner than CLP, take a look at the maintenance & cleaning forum for details and instructions. There are also cleaning products like barrel extension cleaning star patches, I had used CJ Weapons Accessories (web address below) cleaning star and Bore Stay upper receiver cleaning rod guide to clean all my AR. Watch the video at the CJ Weapons site to see how to properly clean your AR chamber. Make sure you clean out all the factory preservative lube using a weapons cleaning solvent, then lube it per the instructions link below. I'm using SLiP 2000 cleaner and EWL lube which are better than CLP, I had used Break-Free CLP way back int the 1980s and 90s but there are a lot of modern synthetic lubes available now. http://www.cjweapons.com/ http://www.ar15.com/forums/f_3/7_Maintenance_andamp__Cleaning.html http://www.ar15.com/forums/t_3_7/548967_AR15_LUBE_POINTS.html |
| I just bought my 6721 a month ago and never noticed the brown stuff. I have fired about sixty rounds thru it so far and it has not affected the operation. but I don't have a proper bore brush yet. and i used clp cleaner to clean the rifle. now i know i also need a a stronger bore cleaner. |