You implied that you might be partial to a Patriotic theme... here are a few ideas:
1.) Minute Man Arms - Then you could name each model after revolutionary figures (i.e. "Revere" for Paul Revere).
- Each model could have a number as its designation (like Surgeon also does... their short action is the 591). In this case, each of your numbers would be the year of a significant date in history that led to our independance (i.e. 1773 - Boston Tea Party, 1776 - do I need to explain that one?, 1783 - Treaty of Paris, ending the war and establishing US sovereignty.)
2.) Revere Arms - Reflects back to Paul Revere and the establishment of our nation's independence. Also a play on words, implying that these receivers are worthy of reverence.
- See above for ideas on model names.
3.) Revolutionary Arms - Again, reflects on the establishment of our nation. Again, also a play on words in two ways... implies that there is something really special and new about these receivers... having a rotating bolt locking mechanism, the bolt makes about a 1/4 revolution as it locks into the breach.
- Each model could be named after a significant battle in the American Revolution.