I definitely agree with this. Let's wait for what will Al Flaherty's gonna say. As a shooter from Toronto, this is the only one serving the area and I must say the staff are good and knowledgeable. Let's give them a chance to clear this issue.
And I can attest to that.
OP here, final outcome of this situation below.
I went to Flaherty first thing in the morning before coming in into the office. The gentlemen there were very courteous & helpful. The main guy (manager maybe, I don't know them personally) asked to see the bullets I was bringing back, inspected them and rapidly agreed that I was correct and that there was something wrong with them (and unlike some people on this forum, never suggested that I might be responsible).
He sent me to the back where the ammos are stored with a younger clerk who started opening boxes to find & validate a replacement. After opening 5, it became obvious that they all suffered from the same problem. We found one that looked better (all the headstamps were the same, and they all had the same height), but even then they showed bulging around the bullet seating. All the similar boxes of 50 I saw there were flawed. That was also the only brand they had.
But then the guy fetched a "value pack". They are the same winchester 115gr, but they come in boxes of 100 and are just loose in the box without the neat little styrofoam holding tray. Even to my untrained eye, it was immediately obvious that these were right. The headstamps were all "win 9mm luger", they were all equally clean and shinier than the others, they were all the same height, and they showed no bulging what so ever.
Since I had bought 3x50, the guys proposed to give me one of those and keep opening boxes of 50 until we found one that was OK. I told him that I had somewhat lost confidence in the boxes of 50 and that I would be more comfortable grabbing 2 value packs, paying for the difference as appropriate.
The guy didn't hesitate for a second and apologized for the inconvenience. I paid the difference and
left a satisfied customer. Incidentally, the value packs are cheaper, so I put in only $6 more and left with 50 bullets more (2x100). So I'm happy.
Props to Flaherty's for handling this like pros. They are currently pulling their boxes of 50 off the shelves and opening them to check. Discussing amongst themselves, they mentioned that they'd bring it up with the winchester guys. So it looks like it was a bad batch.
Thanks everyone for their input.
P.s.: I can also post pictures of my receipts, visa slip, and exchange receipts if my word is still being questioned.