When I was taking the moderator off my rifle this evening, for no particular reason I sniffed the threaded end of my moderator and to my surprise I picked up quite a sharp smell of ammonia. After a couple of sniffs the smell wore off or my nose packed up - not sure which. For the record I am using a T8 Reflex on a Mauser M03 6.5 x 55, firing Hornady ammo, and the thread on the barrel gets a light application of molybdenum grease. It reminded me that back in the autumn I helped a friend zero his rifle and we observed what appeared to be vapour and a very strong smell of ammonia from the moderator at each shot. The set up was a Sauer 6.5 x 55 fitted with a modular moderator, Atec I think, using a variety of ammunition. While his rifle grouped well without the moderator, it could not not manage a 6 inch group with the moderator. He bought it second hand with the original thread cut off ( ie barrel shortened) and had it rethreaded. It appears from shooting at paper that the moderated shot may be tumbling as the target seems to show slight signs of tearing from moderated shots.
My friend said that he had stripped and cleaned his moderator using washing up liquid as per instructions, so the vapour may have been moisture, but can anybody explain the smell of ammonia in both cases? And was I imagining the tumbling from moderated shots?