This is a two year old thread but as it has resurfaced, a concern regarding the use of plastic bags is that they can be torn if slid across the floor. That can make a mess of things.

Like others have mentioned, I use plastic bins because they are much less likely to tear and mice are less inclined to chew through and set up housekeeping in the stash. Bins also stack much easier and their square shape allows more efficient packing. I use 25 gallon bins for 12 ga as I load a lot of them and that is the largest size I can move easily in a confined space. I have one bin for Winchester AA, one for Remington STS and Gun Club, one for Reifenhauser hulls. 16 and 20 ga utilize a 15 gal bin separated into Win/Rem and Reifenhauser hulls. 28 ga is a pair of 10 gal bins and 410 is also 2 bins, with one for 2.5" hulls - Win AA loose inside with Reifenhauses kept in Ziplocks and the other for 3" hulls with AA loose and Reifenhausers in Ziplocks.