There are at least a few threads on here discussing the stuff. The gist is that you should probably use quality brass cased 5.56 for break in but the wolf will work fine in the rifle. It might not cycle properly on the lower gas settings. It is cheap for a reason, though. Granted, I've got a case collecting dust until my XCR shows up later this month or next.
IMHO/E Each rifle is distinctly different like and no two are alike. Some may prefer it, some may tolerate it and some may not at all.
If your rifles chambers walls are smooth enough extraction should not be much of an issue.
Brass is a relatively slippery metal and brass cases, when fired, "spring back" ever so slightly.
Steel cases do not. They tend to grip the chamber walls a bit more than brass cases. The carbon residue adds traction if you will.
The various coatings on steel cased ammo are as much a lubricant to ease extraction as they are a corrosion inhibitor.
The military classic 5.56mm bullets although lead cored are copper plated soft steel jacketed. Which causes me to wonder about their fragmentation characteristics or possible lack thereof.
I have friend who owns an AR-15 that functions flawlessly with Wolf but accuracy is poor. Another gets good groups but horrible function. I know a AR180 owner that gets "acceptable" performance. Another who owns a M96 that functions best and groups tightest with Wolf 62Gr. Ammo.
I guess their newer stuff, the poly coated, is a litle better than the older laquered cases. Either should work just fine though. Just make sure you pay a little extra attention to scrubbing out the chamber when you do your PMCS and cleaning.
I was not saying avoid Wolf ammo.
Merely relating that results can and do vary and a few of the many reasons why.
The only way to know if Wolf military classic or any other ammo/gun combination will produce the results you are after
is for you to test that combination and determine if the results are acceptable to you for your purposes.
I have a theory as to wolf and stuck casings in general. after much experience with this, I have a working theory that it is DIRECTLY related to the amount of gas the operating system gets. If there is too little gas the timing of the bolt opening will be off. this is important with steel case stuff as it contracts at a different rate than brass thus leaving us with a smaller window to extract. excessive carbon build up or a slightly underpowered round could cause this to happen where the gun was "a bit too light with the gas" and the user was running low powered ammo like wolf anyway. the combination of the two could create the stuck case scenario with some frequency in some folks guns where other folks would have no problems at all. also the cut of the chamber and it's finish might be a major factor as well.
The XCR and guns with gas settings are particularly well equipped to deal with this issue. If you have any issues with the ammo at all then crank the gas up and keep shooting.
Here are a few OTHER things that may also help proper cycling:
-chrome lined barrel and chamber
-proper lubrication (not too much not too little)
The XCR should have no problem running wolf. you should run it on 3 or 4 gas setting tho. when in doubt go higher.