The HK 53 is the short carbine variant of the HK 33 rifle. It is often classified as a sub machine gun due to its compact size. The HK 53 looks like it has similar proportions as the MP5, but the magazine well and forearm and flash hider are longer, making it a slightly longer weapon. The flash hider is longer and of a four prong design while the flash from such a short barrel is much larger. Virtually all HK 53Â’s are fitted with a retractable stock, making them the HK 53A3. It is possible to fit fixed stock, resulting in the HK 53A2. During its production life the HK 53 received upgrades similar to the HK 33E such as a new retractable stock and a new flash hider but was never rebranded.

The HK 33-K is the carbine version of the HK 33 rifle. Except for the shorter barrel it is completely similar to the full size version. Most HK 33-K models are fitted with the retractable stock, making them the A3 model. With a fixed stock it would be an A2. A bipod and 4x scope are optional, but uncommon on the carbine model. Over time it received the same changes as described in the full size model.

The HK 33 is the standard full size rifle model of the HK 33 family. It is available with a fixed stock in the A2 model and a retractable stock in the A3 model. During the production lifetime the HK 33 received several upgrades. These included ambidextrous burst fire trigger groups, new concave retractable stocks and the twist was changed to a faster one for use with NATO ammunition. The improved versions were sometimes sold as the HK 33E, with the E demeaning Export. A bipod and 4x scope are optional. Scoped rifles should not be confused with the HK 33SG/1 model that delivers better performance as a marksman rifle.

The HK 33SG/1 is a similar sniper development of the HK 33 as the G3SG/1 is of the G3. Most of the rifle is similar to the full size HK 33. The barrels are handpicked for accuracy, a cheekpiece and bipod are fitted and a 1.5-6x Zeiss or Schmidt & Bender scope was fitted as standard. The trigger group is replaced by a set trigger group that allows for semi automatic and full automatic fire. In semi automatic fire a button behind the can set the trigger for a very light and crisp trigger pull.