The M16 also has a loose firing pin, and extracting unfired cartridges will sometimes show a slight dent. Milspec ammo with hard primers aren't an issue. However, civilian ammo, or loads using soft primers have been noted to cause the problem. One alternative cartridge I looked into for a build was noted by fans to be suceptible to slam fire if you hand chamber a round thru the ejection port, then release the bolt allowing it to move forward without the friction of stripping a cartridge and chambering it. That was enough to energize the firing pin with enough force to set the primer off.
Military self loading actions are often designed for use with hard primer ammo as a working component, our DOD only offers a few loads for official use. Hard primer required. Since the AKM is using a floating firing pin I expect that would be part of the package, too. Its not US or Russian, it's Engineering vs Liability, albeit America has an overblown case of it. LIke, self retracting blades on box knives, or me buying a watertight laptop case and keeping it away from my wife's travel cup.
That was a long vacation with no internet. I had to learn what 1985 was like again.