I haven't done this and sure wouldn't without a letter from the ATF but do you think that this would be legal?

Could I build a single shot AR-15 with one of the California-type lowers that doesn't have a magazine well into a complete rifle using M16 trigger parts?  

Fortunately, I don't live in California so my primary concern is with fedal law.  This is a question that I came up with after reading about the single shot AR-15s lowers for California.  The rifle could not be modified to shoot more than one shot per trigger pull because you have to manually load a new cartridge each time.  There is no place in the lower to insert any type of magazine.

I understand that because the rifle is single shot that it could have all of the features that are banned on semi-autos.  This is a curiosity thing for me.

Thanks

I'll tell you why!  DPMS has a pump action AR-15 out.  A friend of mine with the Sheriff's office wanted to put M-16 parts in the lower to make it smiliar to an old Ithaca model 37 slam fire pump.  Since the receiver on this DPMS gun can not possibly use a semi auto upper he wanted to know if it would be legal.  The only way to find out would be to write ATF.