Like its established AR-platform competition, AK’s come in a huge variety of styles, levels, grades, and configurations. However, unlike the AR, its common for those rifles to vary wildly (relative to the AR) due to the lack of a solid TDP that various companies work off of. As a result, especially on the low-end of AKs, the action has a tendency to be much rougher than the AR. While yes, AR’s can be rough, its not typical to have the bolt carrier hang-upon on its own receiver or hammer.
Typical causes for this are unrefined rails (typically just welded in) and a hammer whose shape can cause the action to hang-up if charged slowly. While, yes, the AK will eventually shoot itself in, there are some relatively simple steps that one can take to smoothen out their action, which primarily revolves around the hammer of the rifle.
The AK guys runs through this home-brew machining in detail. The only tools required? A file, dremel, and some sandpaper (typically you will want 100-180 grit for basic metal work).
Basically, pull out the fire control group, round out the hammer, and remove the surface inconsistencies common to stamped and bent metal. Once done, a rifle will be noticeably smoother and the hang-up found in certain brands at the rear of travel will be gone.
The only drawback? You can remove some protective finish from the operating components.