Those of you doing well with Wolf ammo are probalby more lucky than anything else.
I have been working at Los Altos Rod and Gun Club for three years now, and have seen my fair share of oddities. Here are a few:
Lacquer buildup - yes, it does happen. It tends to cause stuck cases more than anything else, and requires diligent use of the cleaning rod and brick in extreme cases.
Primers - while they are getting better, Wolf is second to CCI Blazer in failures to fire that I have seen.
Cases - The AR chamber (and most American firearms in general) is designed specifically to feed and function with Brass cases. Difference? Brass has more "spring" to it and shrinks slightly more after firing, while steel tends to stay conformed to the chamber. This can also lead to sticky extraction, and the use of the "pull and bump" to strip the case out of the chamber.
Bullets - Wolf used to use Steel jackets for their bullets, and some older batches can still be found. Steel on Steel = F'ed up rifling over time. This has been corrected - jackets are now a modified gilding metal alloy (extra Tin and Lead, I think) Steel cores are still, IIRC, fairly common. Steel cores are not a problem with the AR - SS109 is steel core and my homebuilt preban made from assorted parts eats the stuff all day long.
Quite a few AR problems are user related - generally caused by overoiling. The extra coe and ash created by the propellant used in Wolf Ammo causes these problems to compound each other, and can cause all sorts of strange malfunctions.
I have only seen one case of breakage, and it is something that was aggravated by the use of Wolf ammo, and not directly caused by it. I found an extractor claw lying on the bench, and upon inspection found that the casting for the claw had a "void" - miniscule air pocket. The case may have stuck just enough to have caused failure of the claw and breakage, but this is something that still would have happened (later) using brass-case ammo.
For people wanting a good, cheap ammo to use in their ARs - I most often recommend Euroammo surplus (Portuguese and Spanish work well) or American Eagle (made by Federal Cartridge Co, the same people that brought us the Hydra-Shok.)
I mainly shoot Spanish - Santa Barbara Armoury production - SS109 surplus and love it. I will also shoot Lake City or WCC when I can find it, and LC is my personal favourite.
If you reload for your AR, make DAMN sure you full-length resize EVERY time, or you are asking for malfunctions. RCBS has released a new style of die that is supposed to limit or eliminate case growth in FL resizing, and I am awaiting reports. I think they call it the "X" die. Anyone care to offer info on this?
One last point - for those of you who buy "gun show" or "white box" reloads - DO buy a case headspace gage. I have found it common for these cases to NOT be FL resized (in .223, .308, 9mm, and .45 ACP) and this causes trouble in semiauto firearms. The gage is cheap enough (you don't need a Redding, a Midway gage will serve well) and give any "white box" ammo you have a good spot-checking before it goes on strippers or in mags.
FFZ