So this has happened to me about 4 times. When i change weapon on loading screen the game freezes. The music will still play but the screen goes black. Im playing on a SNES cart from my childhood, so i don't know if it's just old or what. Anyone else have this problem? I guess I'm asking if I need a new cart or if this is something common.

I think Elmagusses guide mentioned this initially that its risky to change weapons when zooming out of of a screen because there is a high probability that this will happen. That is why it was recomended to only do so when the game is loading the screen back and not when its "closing it". Happened to me a couple times and realized this is why it was not recomended

Yeah, this is a good 'ole crash. According to Calmlamity, it occurs on a specific frame as a screen transition is loading in, and if you press the L button on that frame you will crash. Happens on EMU and cart.

You can avoid this by holding a directional button while you click buttons, or obviously just not touching the shoulder buttons.