Re: Plastic guns and sand?
I had zero problems. I carried a Glock in theater for a good amount of time. Without derailing this thread and going off into a discussion of how, I'll share my experience.
A Glock DOES need to be lubricated. Dry Glocks will run for a few rounds before they start to hick up when they are full of dust. How many depends on how much Jesus hates you and how much crap you have in there. If they are properly lubed, they will continue to run. This means grease, not oil. Oil sucks unless you use a lot. I had much better luck with oil in rifles than in sidearms. Using enough oil in a sidearm seemed impossible or a damn mess.
Just because it is a Glock, some people feel they can forgo regular cleaning and daily detailing. This is a mistake. The issue becomes exacerbated after harsh exposure. Holster design can really help keep the crap out. Not rolling around on the ground or standing like a dunce in a dust storm does little to help things.
I'm told the HK's are even more tolerant because of the hollowed out slide giving the crud a place to go and not get in the way. I have no first hand experience with this. I can say the HK's make better suppressor hosts than the glocks. I suspect the reason is the same.
What problems are you having?
What is it that you are doing?
How are they retained?
I can ASSURE you, I've not seen anything all metal run better in that environment. If I find myself there again I will have another glock at my side.