The bearings used to be stocked under NSN 3110-00-158-6691. There are surplus distributers in the USA who have a network to deal with surplus stuff and will give quoted based on NSN. A google search will bring some of them up.
Here I found a couple hundred of these bearings contracted for by the US military over the years at this page:
http://www.partslogistics.com/demo/s...e=nsn&x=10&y=5
Another search on another site shows this NSN to be cancelled.
The NSN also lists about 6 or 7 different part numbers for this bearing with twice that in manufacturers.
Part numbers include :
928
A1570
K5756
1828X37
6113
1760-011 or 1760-0011
1228GG267
Price listed back in 1984 was $68
I can research it some more with regards to what manufacturers used those part numbers, but at present my NSCM pages are downstairs somewhere.