glock 19 malfunction

Question
I have fired approx. 150 rounds from this weapon with no problems. The next time I shot it the casing jammed after the last round in somewhat of a "stovepipe" fashion. I had to vigorously pull the slide to clear it. I changed magazines and it did it again. I fired about 60 rds alternating the magazines and it did it every time. I suppose it could be the magazines but it seems unlikely for both to be bad.  The gun and magazines were purchased new and the ammo was new.

Answer
Sounds odd, you said it jammed every time was it the last round every time or different rounds.  IF you keep you mags loaded the spring could have been pushed too long and now it is failing to push the last round with enough pressure. Your question is not clear is the jamming round after fired or when loading?

It is either one of three areas, the mag spring, the ejector clip or the feed ramp, the ramp is probably not it since all the other rounds are loading fine and the ejector is probably not it since it is ejecting every round except last.

I would take mags a part, clean, and stretch spring out a bit. So measure the spring after you take it out and then stretch it so it is an inch longer when resting out. Then put mag back together and see if that works.