a bit of a problem with that though when using the SU-76... for starters it lacks accuracy and even when its shots do hit it only does 120 damage... the old SU-76 at least compensated for its bad accuracy with high rate of fire and thus i employed it much like cavalry... a shock tank i would rush into the flanks of a big tank while the SU-85 snipes it/keeps it distracted/abuses its low target size to kite shots... and get out using its speed... it was essentially much like the puma... in its old role...
the patch however reduced its DPM and anti infantry potential respectively... which means it no longer fits its old role as cavalry... in fact it no longer fits any role efficiently... the puma is better at its supposed role as anti light vehicle/cavalry... and even kills infantry better when not using the barrage... in fact its soo bad at killing light vehicles now that when opponent brings out an SU-76 i simply just rush it and kill it... its simply that bad...
SU-76 is there to poke your opponent at far range and jeopardy a potential rush. the unit is fast enough on backward to hit twice at max range before being really threatened. If you can rush a SU-76 and kill it, it only means the unit was overextending.
Old SU-76 was too good and could simply be used as main AT and Arty unit when spammed. Both Stug and SU-76 have been logically nerfed and cannot sit there and outperform more expensive units in there respective function.
SU-76 is still a excellent stop-gap vs Pz4 rush but you can't simply rely on it to deal with your opponent's armor. Which is great.
Build one to support your troops and then go T4 for more firepower.