Forged vs. Cast

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.

2 thoughts on “Forged vs. Cast”

  1. Here are a few of my theories as to the perception that casting is inferior to forging:
    Forged Vanadium steel tools vs cast junk metal tools from the far east. When you bend or break the wrench working on your bike with that $19.95 kids tool kit that you got for Christmas, you notice that Dad’s tools are forged and do not break. Hence the mindset that Forged is better is born.

    There have been a couple of overzealous posters to the gun news groups that would emphasize that their semi version of Korean War Era rifles were built on forged receivers, not rewelds or the “inferior imported” cast receivers that were winning all the matches at Camp Perry. If a forged rifle is the choice of the grizzled old posters on UseNET, then the premise must carry over to handguns.

    It makes me wonder how many of the people who sneer at a cast or alloy frame on a 1911 also tout the superiority of injection molded polymers over all that archaic metal.

    If the engineering is correct, then the material will handle the load. How many piston rods are now cast vs forged? the cast pistons and rods in a little econobox car take a far greater beating driving to work than just about every gun made. Think about idling at 1000RPM – that would be the equivalent of 1K slide racks a minute

    That is why I look for fit and finish on a gun, they say more about how well it is made and what to expect than what material went into it.

    I have a true forged 1911-A1 – an original Remington Rand from 1944
    and I have a cast frame, Stainless Frame, alloy frames, and would get a carbon fiber framed 1911 if they perfected one. I even have a tupperware gun.
    I only dislike the Scandium, since wear shows up more and are a bigger hassle to refinish or touch up.

  2. I’m not a metallurgist either, strictly speaking, but I am an engineer.

    Forging is king if you want a really tough part. For fracture resistance, arguably the main consideration with a firearm frame, forging aligns the grain structure to follow the surface, which helps resist crack propagation. With hot working you’ll also get a fine grain structure.

    This isn’t to say you can’t get a perfectly good casting to do the job. If the heat treatment is good, strength should be fine. However, you won’t get the aligned grain structure to help fracture resistance, and it’s a lot less effort to do a cheap crap casting than a good one. Hell, I once cast aluminium at school, but I wouldn’t have trusted the mechanical properties of that piece with my life.

    I’d say this is like 90% of engineering questions. How strong does it need to be, and how much do you want to spend? Sure, forging has the potential to be best, but (machined if necessary) castings are probably good enough for most work, and cheaper. As for the Rugers, my guess is they also use that other time-honoured engineering solution, throwing lots of material at the problem to bring the stresses down.

    No call to go spending more than you have to, unless you want to.

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