So far as I can tell, there doesn't appear to be a way to thread a milspec buffer tube on the pistol lower. On a different note, it does appear that a Midwest Industries end plate adapter (http://www.midwestindustriesinc.com/index.cfm?fuseaction=category.display&category_ID=97) will fit on the end cap for attaching a sling. I ordered the MCTAR-13. I'll report on how well it works when I get it.