If you hang out on internet gun forums long enough, you will eventually hear people arguing about forged frames vs. cast frames on firearms. The argument is that a forged frame will hold up better over a long period of time than a cast frame. Not being a metallurgist, I decided to go out and get some education on the difference between forging and casting, and I was actually pretty surprised by what I found out. Before I did some research, I was generally part of the “forging > casting” school of thought, not for any good reason but rather because that was what appeared to be the general consensus, and since I was relatively ignorant on the issue, didn’t feel like sticking my head up. I knew my Paras had a cast frame, but they seemed to be fine so I didn’t worry too much.
Now, I kind of knew what went into forging a frame, but to give you a basic idea, a forged firearms part is made in much the same way you see swords being made on the Discovery Channel, albiet with more modern tools. Essentially, modern forging takes a bar of steel, heats it up and then whacks it into shape with a multi-ton hammer and a set of dies. Pretty much the same process that’s been used since we discovered metal, just faster and with better tools.
With casting, the most common form used by the firearms industry is investment casting (note: I could only find a couple of manufacturers that specify that their cast parts are investment castings, Ruger and Para are a couple of them) which uses wax molds to create the shape of the part being cast. Investment casting requires some machining after the part has been created to remove burrs. However, with modern CNC machines combined with investment casting, it’s possible to produce extremely uniform parts with little to no variation between the parts for a lower cost per unit that forging.
Before I continue, I need to restate that I’m not a metallurgist, so take that for whatever it’s worth. However, in my research I’ve found that it seems like the most important part of creating a cast frame for a firearm is the heat-treating process. Apparently, when the steel is heated to the melting point, the grain structure gets bigger (steel has grain structure? Huh. -ed), which means that if the heat-treating and cooling process isn’t done correctly, then you’re going to end up with a crappy part. Bigger grain structure = weaker steel, it would seem.
I can’t find anything that indicates that a properly heat-treated investment cast frame is any less durable than a properly heat-treated forged frame; however what I do find are a lot of references to cast frames and parts made in places with spotty quality control, steel of an unknown variety; which leads me to wonder how those places are heat treating their cast frames.
On the flip side of casting, Ruger uses investment casting for their guns, including their revolvers, and if you’re a reloader you know that there are pages in the reloading manuals labelled “Ruger Only”. I think what it comes down to is that if you’re really worried about a cast frame, then don’t buy a gun from Joe’s Fly By Night Arms Co. located in some third world hellhole. I’m pretty comfortable saying that if you buy a gun with a cast frame from a reputable manafacturer such as ParaUSA, Ruger, or STI, then your gun is going to last for more rounds than the average person will ever put through it.