[Ukraine Train]

I always thought that milled receivers were preferable to stamped because the tolerances end up being tighter but then I was reading about the VEPR rifle and it mentioned that the original AK receivers were milled but then went to stamped because they are better in some way. Opinions?

[Langenator]

IIRC, the original AK receivers were milled, primarily because Soviet industry wasn't able to produce stamped ones. Once they got set up to do stamped receivers, they switched over. This was the primary distinction between the original AK-47 and the AKM.

[Ukraine Train]

I found the site I mentioned.... http://www.impactguns.com/store/vepr_k_7.62x39.html


The first AK47s had machined receivers. Later the Soviets produced the AKM47s (the "M" stands for modern), the Soviets found that stampings were not only more efficient to produce but resulted in longer receiver life and better accuracy than the milled receivers.

[Gary G23]

Stamped receivers are used because they are a LOT cheaper to manufacture.

[Ukraine Train]

Yeah I know they're cheaper but what I'm confused on is that site says that stamped is also better for accuracy than milled, I've always thought the opposite.

[4v50 Gary]

Stamp v. milled for accuracy.

Well, it comes down to rigidity and the flexing a receiver undergoes upon recoil. Think of the receiver like a tuning fork that vibrates upon recoil. The more rigid the receiver, the less likely it is affected by other stresses including use of the sling (and if pressure varies, the stress varies and changes the harmonics). A good example of a stamped reciever that was beefed up to make it more rigid is the HK PSG-1. Based on the G-3, the sides (where the collaspable stock would collasped into) has additional strips of metal welded to its side to add to its rigidity.

General rule of thumb is that the machined receiver (thicker metal) is more rigid and flexes less. However, 90% of your accuracy is going to be in the barrel.

[JNewell]

I don't know which was the original configuration, but it's good odds that if the rifle was originally designed around a stamped receiver that it could function best, and maybe even most accurately, made that way. Many guns are designed with their manufacturing methods in mind, and they don't necessarily do as well when translated to another method.

[scotjute]

Just guessing, but perhaps the longer life of stamped receiver is due to the milled receiver either improperly designed (to thin for the stresses) or sub-standard quality casting.
Thoretically, a stamping has the same inherent benefits one gets from forging, only you've used sheet metal instead of a bar or plate of metal.