Not to try and rake anyone over the coals here... But I would advise against shooting the lacquer coated steel cased ammo at any time.
According to the manufacturers that I deal with on a regular basis, and according to the U.S. Army's Aberdeen Proving Ground, the use of lacquer coated steel cased ammo will cause exceedingly high chamber pressures due to the fact that the heat and pressure of the fired round causes the lacquer coating to leave a residue in the chamber (chrome lined or not). That residue continues to build until one of two things happens: 1) the rifle/carbine will finally suffer a catastrophic explosion (aka KA-BOOM!) due to the excessive pressures within the chamber because the empty case is not being extracted quickly enough and the pressure rising beyond the limits for which the system was designed. (This situation is one I have witnessed three times in the past 7 years, so YES is does happen.); OR 2) the pressure in the chamber rises so quickly that the case head is ripped off of the rest of the cartridge, requiring a broken case extractor in order to get the rest of the cartridge removed from the chamber. (I've seen this more times than I care to keep count. Ever wonder why the "broken cartridge extractors" for 5.56 NATO started showing up in the market at about the same time as we started seeing huge imports of 5.56 NATO steel cased ammo being imported from China and Russia? Well, now you know.) These two things are the worst case scenarios... Other problems, such as failure to extract completely (stovepipe jams) or partial extactions causing double feeds may also result. Stuff like that can at best make your day at the range a pain in the butt, and at worst make your day at the range turn into a run to the Emergency Room.
We have departments that send their officers to our classes with this stuff... The departments are trying to save money, and that is understandable - but not at the cost of personal safety. Sometimes we have no choice but to let them fire what they brought - and we have trouble with it by the time we are three hours into the range course. Not all of the steel cased stuff comes from China or Russia. I have even had officers bring in steel cased ammo from Hornady - that happened last December and was a new one to me. When I asked about how they ended up with the steel cased stuff, they replied: "We told them to get us some good quality ammo from Hornady, expecting to get Hornady TAP ammo. They bought Hornady, but bought the cheapest Hornady they saw on the list. This is what we got (pointing to the steel cased Hornady.)"
So, coming from someone that makes their living on the firing range, and that sees hundreds of thousands of rounds fired per year, IF IT WERE ME, I WOULD LEAVE THE STEEL CASED AMMO TO THE AK-VARIANTS, AND STICK WITH BRASS CASED AMMO FOR THE AR SYSTEMS. The only proper way to get the residue left from lacquer coated rounds cleaned from the chamber is to use an extemely strong solution containing acetone or a like substance (Hoppe's #9, or even Tetra's extreme solvent is not enough - the ammonia that cuts brass and powder fowling will not cut the lacquer residue), along with a good chamber brush and lots of time and elbow grease. Most people don't take that kind of time or effort in the cleaning of a weapon. Without the hard effort, the residue may be thinned, but not entirely romoved. That just delays a problem that is sure to come.
Look at it this way... Would you pay $1000-$2000 for a fine AKC registered dog with really good papers showing a champion bloodline, and then feed it table scraps and Ol' Roy dog food from Wal-Mart? No... You would feed it good quality food like Pro-Plan, Hills, Iam's or Purina One along with whatever else your vet tells you to feed it when you seem him on a regular basis. That is, if you care about your expensive dog's health... It is the same way with the AR-15/M-16 weapons system. Why buy a pure bred, finely machined weapon and then feed it cheap, unhealthy ammo?
Well then, why do Wolf and the others make steel cased 5.56 ammo? BECAUSE THEY KNOW SOMEONE WILL BUY IT IN ORDER TO SAVE MONEY. Russia fully understands capitalism now, and they will manufacture and sell whatever they can (ammo, night vision gear, etc. - all from what used to be government owned factories) to strengthen their economy. Do they care about the end-user? No. What happens if your weapon blows up using their ammo? You can't touch them, as far as any liability goes. But if you have a problem with Federal, Winchester, Remington, Hornady TAP, or any other quality U.S. made ammunition, you have some recourse. How much I do not know - but they know that they have to produce quality or they can loose their butt in a civil suit.
Just my 2 cents worth... I'll leave it at that.
Regards,
Mike
PS: I have used 5.56NATO brass cased ammo from S&B (Czech Republic.) It is a fine military spec ammo in a brass case, and will work well in your AR - but it doesn't smell good like U.S. ammo when fired! PEEUUU!!