I use a Dieter/CQD end plate.
[img]http://photos.ar15.com/ImageGallery/Attachments/DownloadAttach.asp?iImageUnq=15841[/img]
[img]http://photos.ar15.com/ImageGallery/Attachments/DownloadAttach.asp?iImageUnq=15842[/img]
I bought it from MSTN [url=http://www.ar15.com/forums/topic.html?b=7&f=25&t=148479&w=myTopicPop]here[/url].
CHRIS