I am not sure why people keep bringing this up but it has clearly been demonstrate the PTRS Penal have similar DPS with other AT infantry vs mediums.
People keep bringing this up, because chip damage is irrelevant, only burst matters, unless you're fighting a no micro scrub who just parks his tank in front of AT squad and alt-tabs to jerk-off, in which case, as was proven by tests, the tank still wins.
This is EXACTLY why 251 was roflstomping PTRS penals, but was running for its life against PIATs or Bazookas.
I'm not sure why people who are here for years and play since release still have problems understanding how mid/late game AT combat works.