so i was testing my 400W MV lamp (on a 400W MH/MV ballast) and it started to click and pop, since i've never heard this before from any other lamps i've tested i am a bit concerned but i could possibly just be over reacting to glass adjusting to the heat? I'm wondering is this thing gonna blow up on me?

my parents would not take to kindly to that...

I have a 50W metal halide in regular use and it often makes a very soft but noticeable 'ping' sound about 5-7 minutes after warmup is complete. It's probably just that, but I cannot be 100% sure.

lol i take it back.... the westinghouse 400watt lamp does it too.... but it still scares me a bitlol (due to past experiences) both lamps do the pinging noise repeatedly.... infact the westinghouse is doing it rn..... sounds like water dripping down a pipe... the reason it scares me a bit is because im not used to glass taking so long to adjust , and it makes me think of expansion... then explosion, i may just be a bit jumpy lol

It is usually the internal metal parts expanding at different rates than the outer bulb and so it moves on the contact points (the crown dimple,...). And this moving then causes these noises.
If it would be the glass itself, it would mean there are cracks spreading around and so the lamp would shatter by itself after just few cycles...

I have a Sylvania 175w cleartop with RS frame that does this during warmup.

I had a fluorescent lamp that made a *ding* sound every couple of minutes.
And no, the lamp was in my desklamp so it was not a starter.

I've heard this too, just metal expanding a bit with heat.

Metal contracting-expanding due to heat-hear this when I turn some transmitters off and the power tubes are cooling down-hear the same clinky sounds-also on exhaust -mufflers on lawnmowers-the same sound after turning it off and the engine cools off.