I've got one of these and am looking for the mounting brackets for storing the carbines, it holds the full size AR's very well but I need the little wire spring brackets that push the barrel towards the support by way of pushing out on the stock.
Part #NSN 5340-01-230-3181
Can be seen in:
Unit and Direct support Maintenance Manual
for M16A2 and M4 Carbine
May of 1991
Army TM 9-1005-319-23&P
If anybody has any idea what these are I sure could use some.