Cast vs. Forged

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All other components being equal? (Meaning same fire control parts, buffer assy, etc.)

There will be no measureable difference in life expectancy. Both of them will probably outlast MOST shooters.

If you take a job as a contractor in Iraq, and take the weapon with you, I rescind the above statements.:D
 
For the small difference in price I'd go with the forged. Go over to www.ar15.com and ask the same question. I have seen pix of failed cast receivers over there. The upper takes 99.9% of the beating in an AR style rifle but some stress is absorbed by the lower as well. The pivot and take down pins put stress on the lower as well as the buffer operation.

Shabo
 
For the small price go forged. If it was steel, it would be no problem, but aluminum is soft anyhow. Cast receivers tend to be entry the cheapest model that an AR manufacturer will make and attention to detail can be lacking.

A cast AR is fine for a plinker, but no good for a combat or rough use weapon. Lots of info on the www.ar15.com forum.
 
From a metallurgical POV cast stands the greater risk of inclusions and voids - that could weaken the overall integrity.

Forging does for the most part .. consolidate the microstructure and confir greater strength. Any heat treatment later will further modify properties but - the grain should be more uniform throughout.

I'd say this applies pretty much similar re steels and aluminum.

A classic example of benefits of forging is with wrenches ... if the metal flow is shown graphically then it will be seen that the direction goes longitudinally and .... sorta ''wraps'' around the 'jaws' .. with an open-ended I am thinking here. Makes those 'jaws' much more resistant to spreading.
 
I was pondering this very question yesterday. I always ask if a particular receiver that I'm not familiar with is cast or forged because I've been programmed to think forged is better. And I'm sure it is more robust. However, aren't almost all AK receivers cast? And they're generally believed to be more reliable even than an AR. I know their reliablility has more to do with looser tolerances than an AR, but still, wouldn't this indicate that casting may be good enough?

Now, if I'm mistaken, and AK's are forged...then never mind.
 
I know their reliablility has more to do with looser tolerances than an AR, but still, wouldn't this indicate that casting may be good enough?
Click to expand...

It may also indicate that AK's are built as cheaply as possible while the basic design stresses reliability over other desirable features......like accuracy.
 
Folks,
Please don't get me wrong. I'm not an AK fan. I'm just playing a little devil's advocate here. But since the AK is known as a rifle that "takes a licking and keeps on ticking" and given the fact that it's receiver is stamped sheet metal (thanks, Tamara) and NOT forged like standard AR's, can't it be proposed that cast receivers may not be so bad as we are led to believe. I'm not saying that they are or they aren't, I'm just trying to open up the discussion here a bit. I'm as curious as the next guy. But I want to know the truth here. Is it a fact that cast receivers are really that bad or do we all think they're bad because it's been pounded into our brains as fact so much here on the internet.
 
If the weapon is designed around a cast receiver (like Ruger revolvers, for example) then it'll be fine, even very strong, with such. However, I'm told that cast parts being used to replace forged parts can cause problems, and that makes sense to me.
 
I always wondered about this so I contacted an Army Buddy who has a BSME from a very prominant Eastern Engineering school and has worked as an engineer in the firearms industry since 1987, for both defense and civilian-oriented manufacturers.

He says that there is no more than a 10% difference on properties between a properly cast receiver and a properly forged one. As the safety factors are much larger than 10%, there is no effective difference from a consumer's point of view.

That doesn't mean this argument will end. Many people assume forged is better and nothing will change their point of view.

I worked for nine months as a Corporal in an Army Infantry OSUT Company when we were using M16A1's, including an Automatic Rifle qualification. I can't imagine any civilian will wear out any M16 derivative, ever.
 
There are also severe differences in the quality of any particular manufacturing process. The machinery for forging is expensive, so I don't think anyone will skimp on the shape of the dies (which have implications to the alignment of the grain when cool). However, castings (especially in low-temp metals like aluminum) can be made in your basement.

Though there are very high quality (and strong) cast pieces, like much of Ruger's line, my impression is that the cast AR lowers are like that to save money and offer the lowest-cost rifle possible. They are probably not made with the utmost care. I have NOT, however, fluoroscoped or cut one open to see. I don't know. Pure speculation.
 
Cast vs Forged having only small differences is true in steel alloys, but aluminium is a whole 'nother ball game. Cast aluminium is much weaker than forged, as it grows a very large grain structure that quickly work hardens and becomes brittle when left as a plain casting. Forging aluminium and heat-treating it breaks up the grain structure, delaying the work hardening. Do a search on T-7075 alloy and how to make it. Using a tiny bit of scandium works even better, thats why S&W can now make 357 & 44 magnum guns with aluminium/scandium alloy frames where before S&W & Colt were limited to 38 specials with standard aluminium alloy frames.

This may not matter for AR lower receivers; I doubt if they see even 200 psi of force on the pins holding the uppers in, even cast aluminium is that strong. But stay far away from any upper that attempts to use cast aluminium. Yes the bolt locks to the barrel extension, but the receiver frame still gets a lot of force placed on it.
 
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