I thought at the time, maybe they were too short also, but talking to another shooter using a similar rifle, his ammo was even shorter. His was 1.072\” and it did have a similar shape but was a blue cone shaped almost the same, flat on top but a little rounded.
I do use Glock mags 33 rounds, and tried two different ones.
I just received another batch of 135 Match Winners and will load a small amount longer like you (SC) do and see of they work in both the PCC and G34 !!