As noted the early OOW receivers are not fully heat treated except on the ejector rail and the FCG holes.
While a person can make a choice to not use a sheetmetal receivered AK pattern firearm., there are over 100 million of them in service and operating safely and efficiently as one of the most prolific firearms in history.
I suppose one could make the same analogy to an aluminum or polymer or other firearm characteristics used by the AR, Glock and several other firearms. These seem to have a good safety record.
A one-off home build of unknown quality., displaying unknown assembly specs., is by no means a yardstick for judging a standardized firearm model properly assembled with quality materials & skills.
AKB, not dissing the AK. Yes, a ton of them are out there and running for many years w/o issue. I was simply expressing my opinion. And no, I still would not attempt to 'fix' that one. The risk is too great for my blood. JMHO guys, for what its worth.
School me, how would one know that a receiver is one of the non-heat treated ones?
Marcus
Without handling or working with it the example above would be one basic indication. It would be uncommon to see a fully hardened receiver bow in that manner. Of course not knowing all the build and set up of that irregular build is an unknown. It has a cut down barrel, unknown barrel port size, screw build etc.
The example above shows pretty much bare white/silver metal where the paint has lifted which is somewhat an indication of a non heat treated metal surface.
On a non fully heat treated receiver that is in the bare or "white" one could readily see the rainbow/halo effect around the axis pin holes on the receiver where the spot heat treating was done. Fully heat treaded receivers do not have this and are most often darkened as the salt bath and cooling process turns the metal from the untreated silver look to the grey/black finish.
If one were drilling or dimpling , or otherwise working with the untreated receiver it would be obvious in the softness and lack of hardness and spring like return to original shape when flexed.
Drilling a hardened receiver takes some reasonably shard and decent quality cutting tools.,drill bits etc.
Examples here>>
This is a non fully heat treated OOW receiver. You can see the axis pin hole spot treatment and the rest of the receiver as "in the white" silver color.
This is a Nodak Spud fully heat treated NDS3 receiver. The uniform post heat treatment condition in grey/black can be noted and the absence of the halo around the axis pin holes etc.
The type of sheet stock steel plays a [art as well. Though I'm no metallurgist the higher quality receiver manufacturers use the same basic types that heat treat properly etc.
The later production OOW receivers are fully heat treated. Older ones were also marked as ITM and only later as OOW. (Ohio Ordnance Works).
On an assembled firearm with a painted finish it could be hard to distinguish., though often the axis pin halo shows through a blued finish ., but not always on paint or park..
