My own test was shooting a 10 shot group.....then firing 3 x 30 round mags as fast a possible on semi-auto and immediately & quickly firing another 10 shot group.
All done at 100 meters. My group after firing the 100 rounds was tighter than the first group. I have done similar shooting / tests many times with consistent results.
We need to remember the low-cost & crappy issued sighting system with Bundeswher rifles. The one I tested had KAC metal sight rails and a quality red dot.
Several years ago at SHOT (When HK actually brought G36's to the LE Ranges) a buddy and I shot a G36 C with an Aimpoint 2 MOA dot at steel plates at 100 meters (small IPSC style configurations / shape). We probably shot 50 or 60 rounds in a row and were hitting the steel with nearly every shot. This gun was very hot and was being used by numerous other shooters all morning. It was awesome, you just couldn't miss with the gun, smooth operation and as usual 100% reliable function. It had the "new" HK AR15 FOW's mag conversion (SPUHR conversion is actually much better than the HK one) . Trigger was just "ok" and not nearly as good as the nice custom AR triggers, but was perfectly usable.
Rich