I have a partial box of the WOLF 223 primers that actually outshot (by a hair) the SRMs. I was wondering what the difference might be.
The original Russian SRM was said to be no different from the standard (copper colour) SR model in its ignition performance, ie very 'mild', but it had a thicker / stronger cup to cope with 5.56 NATO pressures. Its factory designation was KVB-5,56. I'm still using up the remains of my stock of this model. It's one of the 'toughest' primers you could get, that is in resisting cratering / blanking, but I've found the recent new-model KVB-223, which is probably what your Wolf 223s are, to produce better groups than the old SRM with some powders.