Type 56 vs the AKM
 

What's the reason why the Chinese went with a 1.5mm reciever instead of a 1mm like the AKM? Cheap steel? More durability?

A guy I knew who was in the Soviet Army and fought against the Chinese during a border war told me that Chinese AK's used a lower quality of steel than Russian AK's. Of course I don't know how reliable that is given the boastful nature of Russians.

Funny thing is that the Yugoslavians went with a thicker reciver as well. The extra thickness does stiffen the reciver and adds slightly to the accuracy potential.

Seriously the only members of the AK family I like are the RPK, the Yugo models(Although I like chrome bores), and any Galil varient.

The reason why I hear that the Yugo's went a thicker reciever on their AK was because of the grenade launching.

I'd actually take the AKM over the Type 56. Even though I'm Chinese, I prefer the AKM or even the 103 because

1. The StG-style straightline stock would help reduce muzzle rise.
2. The muzzle brake
3. It's lighter

This is a good question, and one which I wish I knew. I was once told by somebody on another forum that it was because Soviet-made AKMs received by the PLA for evaluation failed their own durability test, so they insisted on thicker receiver metal. But I haven't been able to verify this (indeed, I had never heard of the PLA receiving any AKMs at all, given that the Sino-Soviet split took place shortly after the AKM's service debut in the Red Army).