[deks]

I believe those are magazine carriers similar to this. . .

The plastic carrier fits into the magazine well. . .

"For those who carry a magazine ready with an unloaded rifle. Insert upper part into magazine well to carry loaded magazine horizontally under weapon for instant use. Release, turn mag 90 degrees, and reinsert to load weapon. Keeps dust and debris out of action."

http://www.themakogroup.com/Detail.aspx?PROD=1035003

[William Tell]

deks said: "I believe those are magazine carriers similar to this. . . "

It sure looks like the same product in the pictures.

Although there is a claim that it keeps dust and debris out of the action, it would appear to allow dust and debris into the magazine. With the magazine inserted, then we are theoretically "dust free".

Neither mode of carrying the magazine insures an empty chamber, so I really fail to see the value.

[Dogbert41]

I never saw those before! It does look like it.