In this image is a Colt R0633DC upper receiver conversion kit from around late 1998 (based on analysis of packing materials). The Colt model R0933 was a 9mm submachine gun (SMG) design that was provided to the Department Of Energy for security use.

The model R0633 is more commonly referred to as the “DOE SMG” in reference to the DOE abbreviation often associated with the Department Of Energy.

In addition to the complete R0633 9mm SMG’s provided to the DOE, it is believed that roughly 2000 upper receiver conversion kits were produced. It is speculated that 1500 conversion kits went to DOE and about 500 conversion kits went to the commercial market. I have not seen anything authoritative to support the numbers and item displacement stated.

I acquired this example in late 2022 or early 2023. I cannot recall. Although many of the DOE issued upper receivers ended up being sold on the commercial market, I believe this is one of the original 500 boxed commercial examples based on packaging details and the lack of a factory installed front sling swivel.