Question about M4 magazine accessory

[Contondant]

So I've got a bunch of LAR-15 pistol mags which I've joined together with the v-shaped floor plates from Questar, mostly because I prefer the full-length of a 30 rd mag with the legal capacity of the 10 rd LAR one. Anyways, here's the question:
Is there any kind of cover (plastic?) I could put on the bottom of the lower mag so I can drop it free of the rifle without worrying about screwing up the feed lips? I'm wondering of a cover like this exists to put over the feed lips of a regular 30 rd magazine to keep sand and the like out.

 

[alexD92]

Marstar has some ar15 magazine dust covers, but it seems to say that its out of stock. Try calling or e-mailing John to see if he still has some in inventory.

http://www.marstar.ca/ac-magazine/mag-lg(a-l).shtm

You can also be creative and use some deodorant cap, get it in hot water to soften up the plastic and once its soft enough you force it ontop of the mags, it should get the shape and keep it. its pretty solid too. Plus it gives a nice smell to your mags/guns.

 

[Contondant]

That's perfect, thanks!