Ive heard about some instant munitions wepon rifle thingies that can turn sand into glass and shoot it and make snow into snow balls and shoot them

I seriously doubt that there are weapons in existance that can turn sand into glass, considering it takes immense heat (sun, nuke, etc) to create glass. As for snow, thats a waste of time, the whole ice-bullet thing was proven to be a load of crap.

Another guy on here brought that up, they called it: improvised munitions.

We really didn't see the point in improvised munitions since the amount of energy used to convert these items into ammo could be used as the ammo itself.

Sounds like someone has been reading Deception Point by Dan Brown.

So I'm gonna run into a battle in the desert and start shooting snowballs or icicles at people. Rightttttt

This has been covered before, and quite thoroughly debunked.

As was said above, the energy required to reduce sand to glass would be much better put to use as motive power for an energy weapon, not to mention the fact that any device capable of converting both sand AND water to munitions would have to be very, >very complex, and thus, more than likely, prohibitively bulky.

Besides, a shard of glass or ice just doesn't have the destructive capacity of a gunpowder-launched metal slug. A round from a high-powered rifle causes hydrostatic pressure in a hit target to go pretty much bat#... essentially, it causes a full-body concussion capable of rupturing blood vessels, destroying sensitive organ and nervous tissue, and other such wonderful things... plus, a metal round will ricochet within the body, ripping itself a nice little path of destruction. A shard of glass or ball of ice, on the other hand, would just pierce the target and have done with it; sure, they might bleed a bit, but even a light flak jacket would more than likely deflect a shot from such an armament.

All in all, yeah, it sounds great in theory... but it just wouldn't work properly in practice.