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Posted: 7/3/2003 8:58:26 PM EDT
What is the difference in fit and fuction between a cast and forged lower? And are all PWA lowers cast?
thank you. |
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I have no expierence with PWA lowers. I do have expierence with dealing with cast+forged material. Its just a good "rule of thumb" that anything forged is stronger and more durable. Casting is done becuase its a far cheaper process.
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Every PWA lower I've seen was forged.
Forged is better. But a pre-ban cast will bring 10x the price of a post ban forged... That said... I have about a dozen CAST lowers but no forged ones at present. And that does not bother me a bit. |
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Cast vs Forged again. Everyone has an opinion on this subject, but no one presents any data: shear strength, tensile strength, compression, bending, cracking, vs required strength...where are the numbers? Forged is "stronger" than cast? How much stronger? Does it make any difference? Where are the numbers? What are the aluminum alloys being compared? Who has had a casting fail? Who has had a forging fail? Lets see some data here instead of mindless gum bumping from buffoons who parrot the logic that forged is stronger than cast because they read that somewhere. It may be true of the grain structure of steel, but aluminum alloys? Believee it or not, the rciver of an AR15 has only minimal stresses on it in the first place. All th locking and unlocking isstel to steel, and the alloy receiver just holds the parts together. How strong does it have to be when injection molded plastic can do the job?
Show me the numbers. If you have an opinion, back it up. Or not. |
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As you said again - and that info you ask for - not just opinions - its there in the archives from prior incarnations of this subject. - Including pictures of failed receivers. EDIT: Paid Membership has its perks... - OK I did a search and here are a few good threads on the subject. - But the "Super Thread" which got into the nittygritty with all sorts of verifiable facts and examples has gone past 6 months and has been archived... My Apologies as I had not realized it had been so long. Anyway - for what they are worth here are 3... #1 #2 #3 |
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It's not a tough subject.
A cast lower, is when you take a molten alloy, pour it into a mold, and after you take it out you machine it, and heat-treat it. Properly done, it's a very tough, durable product. RUGER casts most of their frames, and nobody accuses them of being weak. A forged lower, is when you take a bar of good steel, heat it up, and pound it into shape. Then, it's machined, and heat-treated. On a forging, the metal is stronger, and can be heat-treated harder, with less loss of 'toughness'. That being said, it's like everything else, you get what you pay for, if you're lucky. If I have to pay a premium price for a rifle, I'm getting a forged receiver. |
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I've heard of several older cast receivers crumbling after 20-30,000 rounds. I also do not like the whole kaboom factor. Cast works fine, but AFAIK has a shorter life span than forged, and you can't do neat tricks with it (like use your rifle to give someone a boost like they do in the army).
Best thing to do if you have to get cast is to get one from a company that's still around (like SGW) and give them a few bucks to replace it with a forged lower with the same serial number. It's only around $150 or so AFAIK. |
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Cast metal is just that, cast. It is melted and then poured into a mould where it takes the shape of the mould. The process is cheap, fast, and can produce intricate shapes repeatedly. The process is also subject to temperature; too cold and voids appear because the metal solidifies before it can reach the entire mould cavity, too hot and you have size variation from shrinkage. The finished part can be heat treated and annealed to increase strength and toughness.
Forging normally starts out with a blank that is cast in the rough shape of the object to be forged. The blank is then heated to allow the metal to "flow" when struck with the hammer. Then the blank is placed into a die where a series of hammer blows causes the hot metal to "flow" into shape. The major difference between the two processes is on the molecular level. Cast metal often has a uniform crystal structure due to the solidifying of the molten metal. Forged metal often has a crystalline structure that aligns with the "flow" of metal as the hammer blows force it into shape. This causes the material to be harder, stronger, and tougher. Tough metal is capable of bending without breaking and returning to its original shape. Cast metal often doesn't have this toughness. |
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Pretend the subject wasn't AR receivers, so that you can detach your emotions. Here's a bit about aluminum auto wheels:
www.kinesismotorsport.com/forgedcast.htm
Another page: www.forging.org/facts/faq3.htm
You're welcome to believe whatever you wish, but it isn't OUR job to do YOUR research for you. We've done our own. Where is YOUR evidence that a cast part is as strong as a forging? -Troy |
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I appreciate this forum for discussion.
I don't believe anyone who would suggest putting emotions aside and examining the data can be called a "liberal". Quite the opposite. Back to the question, how strong does the casting have to be? And as for specious automotive comparisons, would a forged alternator bracket be superior to a cast one? Particularly if it cost much more? All it has to do is hold the alternator in place. Is everyone here an expert or a gum bumper? If there are experts here, is a quality cast receiver, using a high quality aluminum alloy, strong enough to withstand the stress of a 5.56mm cartridge? The answer cannot be found in reciting "holy scripture" or quoting common knowlege back and forth as though it were proven to be true. Where are the numbers? Who has them, and who is bumping gums? I chose my Bushies bcause they are forged, so I can appreciatee the strenth of a forging. The question is, what are the calculated stresses, and can they be met by a proper casting? Put your emotions aside. Be logical. Think. |
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Yes Spock. |
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It looks like the question has been answered quite competently.
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On a humorous note, I do have a cast lower that is quite a bit stronger than a forged alloy lower.
Then again, it's stainless steel! |
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A number of our members have, over the years, been unfortunate enough to have their ARs involved in accidents that caused damage to them. In EVERY case where the lower was damaged, the lower in question was a cast lower. And we've had reportes from all of the common cast lower manufacturers (Oly, Essential Arms, DPMS).
One guy had his AR in the trunk of his car when it was in an accident. Another guy had his AR slung on his back and bailed on his ATV. There are several others. The point is, the lowers shattered and cracked under the stresses they experienced, and in every case, were beyond repair. In most cases, all of the pieces could not be located. It should be noted that there as NEVER been a similar report involving a forged lower, and I've been here since 1997. Normal civilian use is not going to harm a cast lower. But combat rifles get lots of ABUSE. They get whacked on door jams, they get used as "stepping stools" to hoist soldiers through windows, and they are used to brace falls when a soldier is manuevering. In this environment, cast lowers would fail with regularity. Thus, many of us choose to pay the small extra premium for a forged lower. The same is true for 4150 steel barrels, and chrome-lining. All of those things are extra insurance to make sure that our rifles work when we most need them to. If that isn't a priority for you, fine. No one says it has to be. But many of us have not only book-knowledge, but EXPERIENCE in the field. We know what works and what doesn't. And we know why we're paying the extra dough for the parts we want. -Troy |
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I have been in contact with some people at Oly; the fellow I spoke with acknowledged that forged aluminum alloy is stronger than cast, but that a cast receiver is certainly strong enough to be used in an AR type rifle that will see "normal" stress.
For examples, the front lugs sometimes break off when the upper is allowed to fall forward; and failures have occured when butt-stroking a stuck round out of the chamber. When the chips are down and SHTF as in a combat situation, the forged receiver can be the difference in having a rifle and not having a rifle. The small difference in price would not seem to justify the cast receiver in a rifle that might be subjected to less than careful handling. |
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A small but interesting point - the main stresses on the weapon during the firing cycle are all contained by the bolt and barrel extension, not the receivers. That is why the receivers are made of aluminum and not steel. In point of fact, as the bolt and barrel lock up contains the pressures and forces generated during firing the receivers themselves could be made of anything, all they do is keep everything in place. This was one of the factors that was championed when the rifle was first launched, the fact that you did not need a heavy steel receiver. Any failure of receivers over time is due to metal fatigue and hence the reaso that a forged receiver is the best choice.
Just my 02 |
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I'm going forged, at least until theyv'e perfected a cast beer can. Jeep
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OK. Stupid question here, so be gentle. Are Colt recievers cast or forged?
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Forged,I dont like them for other things but they are forged,my only gripe is the odd ball parts but my first AR was a colt 6601 Hbar and it worked well when I had it,and it was definately forged upper and lower,you can alwats tell forged by the U shaped trench machine in the inside front of the magwell.
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No, not many.
MOST forged lowers will have a ridge running along the center-line of the lower, the ridge is most evident in the trigger area. Most cast parts have RAISED (logo)lettering, whereas forged items often have laser-etching or rolled marks. |
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Devil's Advocate,
I find one of your statements perplexing. You contend that someone who needs emperical data to make a decision is of the liberal mindset while a person who observes results and make a conclusion is not. As a person who respects scientific research and empirical data, let me assure you that my decision making process is not just consistent with conservative thought, but essential to conservative reasoning. The use of random events as basis for an opinion is a hallmark of liberal thought. This use of anectdotal "evidence" is often used to attempt to justify gun control, the Kyoto Accord, and other anti-freedom draconian policies. Please do not confuse my reliance on research data with so-called liberal intellectualism. The best defense of our pro-gun beliefs have come from people such as John Lott. His data is unimpeachable and liberals fear it. Likewise, Bellisares slanderous book was deconstructed because his emperical data was fabricated and he not only could not prove his contentions, he couldn't even prove the existence of his raw data. As an aside, I agree that forged is stronger than cast. This begs the question of whether it matters in an AR type rifle. Also, how much does the quality of casting vary from manufacturer. I own a cast Essential Arms lower. Based on research, my rifle is in the the serial number range of those cast by Ruger. I am not a big Ruger fan, but Ruger has a good reputation as a superior manufacturer of cast products. But even that is supposition; I haven't seen data to back that up. I want to believe my lower is superior quality, but I realize I have nothing to back it up. Regardless of my expressed opinions, thank you for your inputs. Mahatma |
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This is a very old thread.
Some of the "smartest" people in our society are atheists. They are "too smart for their own good"...What I am saying is that we just need to have a little faith in our OWN observations sometime, as opposed to only judging by numbers and data. Not everything in this world is quantifiable. |
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I have a DPMS Lo-Pro upper. It is created using an extrusion process so it isn't forged. That said, they made the walls of the upper about 2x as thick as a normal forged upper so this has a good chance of being as strong or stronger than a forged. I'm sure it has also resulted in a heavier upper but since I'm not a pussy I can carry it just fine. [}:D]
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FORGED IS BETTER SO WHY BUY CAST WHEN THE PRICE IS WITHIN 10% OF THE PRICE OF FORGED .
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I you were building a high performance engine that you wanted to last for a long time, would you use Cast piston rods, or Forged piston rods?
Enough said. |
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My PWA is forged. I'm not sure if they all were. I'm very happy with my PWA. It's very high-quality piece.
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Quoted: One guy had his AR in the trunk of his car when it was in an accident. View Quote I've had a similiar experience, a local deputy came in with his issue Colt. He had it in the trunk of his patrol vehicle in a soft case. He stopped at a trafic light and the car behind him did not. The front corner of the rear car struck near the center of his trunk. The trunk lid had to be cut off to remove the gear stored there. His soft rifle case had a pronounced bend. He brought it to the shop the next day and asked if the rifle could be quickly repaired. Detailed strip and inspection showed that the lower receiver extension (collapsible stock) was bent at the threads. No other damage was found. I installed an A2 stock until his replacement Colt stock came in and he headed to range. This was several years ago and he hasn't had any problems with it. FYI, [url=http://ar15.com/forums/topic.html?b=3&f=12&t=169249&page=1]here's[/url] a thread describing the visual differences between cast and forged lowers. |
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I used to machine both investment cast and forged lower receivers, the forgings are by far superior.
In fact the castings were known to crack apart while being worked. They were also know to fall apart while being assembled. When one was broken while being milled it then had to be destroyed, a couple of hits with a deadblow hammer resulted in many pieces of a former whole part. They fall apart like they were made from clay. Its also true that some companies like Ruger for example know how to properly make a casting, that is for sure, others on the other hand still have alot to learn. Fritze Out |
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Ruger's castings are successful mostly due to the design of the parts. The cast parts are thicker and have fewer sharp angles than would be required of forged ones. With proper design and tight QA/QC cast metal, even plastic, can be used in firearms. It's a matter of knowing what the material will do and what it will be expected to do.
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Quoted: They fall apart like they were made from clay. View Quote Only if there was something TOTALLY fucked up in the casting process. There are many ARs made with cast parts that last a lifetime. |
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Rgr that,
Lots of companys use castings that are fine, I have seen I think it was DPMS cast lowers that looked fine. The ones I worked on where Oly Arms Plinker receivers, although most seem quite happy with them, I wouldn't recommend one. In fact Oly was talking about switching to A1 forgings on their plinkers instead. Its the same with alot of things, if its done right things turn out good, incedently we had a saying, Garbage in=Garbage out. Fritze Out |
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Good Lord dude,
Can't you read? If you are going to be a bench rest tea sipping pinky-finger waving shooter then a cast AR15 lower is fine. If you plan on doing some actual boonie tracking and using your AR15 as a tool instead of an expensive paper hole punch then you would go for the forged lower. You want someone to show you the data? Quoted: Devil's Advocate, I find one of your statements perplexing. You contend that someone who needs emperical data to make a decision is of the liberal mindset while a person who observes results and make a conclusion is not. As a person who respects scientific research and empirical data, let me assure you that my decision making process is not just consistent with conservative thought, but essential to conservative reasoning. The use of random events as basis for an opinion is a hallmark of liberal thought. This use of anectdotal "evidence" is often used to attempt to justify gun control, the Kyoto Accord, and other anti-freedom draconian policies. Please do not confuse my reliance on research data with so-called liberal intellectualism. The best defense of our pro-gun beliefs have come from people such as John Lott. His data is unimpeachable and liberals fear it. Likewise, Bellisares slanderous book was deconstructed because his emperical data was fabricated and he not only could not prove his contentions, he couldn't even prove the existence of his raw data. As an aside, I agree that forged is stronger than cast. This begs the question of whether it matters in an AR type rifle. Also, how much does the quality of casting vary from manufacturer. I own a cast Essential Arms lower. Based on research, my rifle is in the the serial number range of those cast by Ruger. I am not a big Ruger fan, but Ruger has a good reputation as a superior manufacturer of cast products. But even that is supposition; I haven't seen data to back that up. I want to believe my lower is superior quality, but I realize I have nothing to back it up. Regardless of my expressed opinions, thank you for your inputs. Mahatma View Quote |
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Mahatma or anyone else: I have heard the story that Ruger cast some of the Essential Arms lowers, and I have also heard that story disputed by people whose knowledge I respect very much. If someone has CORRECT information--no third hand stories, please--proving that Ruger did, in fact, cast some EA lowers, please share it with us--including serial number ranges and so forth. No flame here, I'm genuinely interested in having this information if it exists. |
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I have a friend who has a preban PWA lower on his CAR15. It is a forged receiver. I heard that about all PWAs being cast, I don't think that's right, perhaps some but not all.
I would not buy a cast receiver, but if for some reason I was forced to, I would get an Olympic, simply by virtue of their lifetime warranty. If it fractures, they will replace it. If a DPMS or other brand cast lower fractures,and it is out the the one year warranty, you are S.O.L. I do think that there are differences in the quality of casting technique, Hesse being at the bottom of the scale. Forged all the way for me. After all, The One Ring, the Ring of Power was FORGED, not cast, in the fiery furnaces of Mount Doom in Mordor! |
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Forged all the way for me. After all, The One Ring, the Ring of Power was FORGED, not cast, in the fiery furnaces of Mount Doom in Mordor! View Quote Not if it is the one in the Lord of the Rings Monopoly set! [;D] FWIW, I personally don't think the stories about any AR in a trunk of a car getting rear ended mean much unless you know the collision speed. If the forged one was a 20mph accident and the cast was a 50mph accident...well, you get the idea. |
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I believe PWA had his receivers machined by Lewis Machine from forgings, PWA has a history with Oly Arms (not a pleasent one).
They made a small run of cast Titanium AR lowers at Oly Arms while I was there, Ruger's Pinetree casting division cast them because Oly's casting house wasn't up for the job. Titanium is difficult to work with, esp machining, but not a problem once the procedures are worked out. Fritze Out |
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The point is: the cast AR had a *shattered* lower receiver. This is a well-known issue with cast parts, due to the pores and grain structure in the metal.
Again, it's pretty simple: normal use is unlikely to damage a cast AR lower. Hard field use (as common in the military) and more extreme abuse is very likely to eventually cause a failure of the cast receiver, whereas a forged part will withstand considerably more abuse. -Troy |
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Again, it's pretty simple: normal use is unlikely to damage a cast AR lower.
********************************* They were falling apart on the cnc machines as they were being machined. They were falling apart whilst they were being removed from fixtures while on the cnc machines. Sometimes, depending on the lot of casting, a scrap rate of 10%-20% due to casting failures and abnormallities was not uncommon, this just in the machining stage. They were known to fall apart, ie crack while being assembled into guns, they also had the highest return rate of all products. The machinists and assemblers loathed them due to their low quality. Why use thwm then, because the consumer wants a lower cost alternative AR. Just don't get them wet. Fritze Out. |
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Quoted: The machinists and assemblers loathed them due to their low quality. View Quote Preach on Brother Fritze! Yeah, I especially liked that the mag wells were too far forward. So much so that we had to relieve the upper under the barrel extension in order to get mags to seat without resistance. Not much you can do about the mag well location, short of modifying the molds, since it is cast into lower. |
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HAHAHA, "death by hammer"
More info [url=http://ar15.com/forums/topic.html?b=3&f=118&t=174501]here[/url] WARDOG7366 wrote: The AR was an Olympic "Cast AR-15". The serial number appeared to be pre-ban with a letter and four numbers. The lower receiver was cast and was a piece of junk. One swift hit with a light hammer and it crumbled like cheap pot metal. If anyone is looking to save $ and buying a cast lower, I would avoid it like the plague. View Quote Follow the link in my post there to good pics of the visual diffs between forged and cast lowers. |
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Quoted: PWA has a history with Oly Arms (not a pleasant one). View Quote Did it ever get sorted out that PWA, as in Pac West Arms, of Washington, was related to the PWA of Milan IL? I [url=http://www.gunsamerica.com/guns/976390110.htm]found[/url] a pic of the PWA logo [img]http://www.gunsamerica.com/upload/976390110-5.jpg[/img] It's as I remember it. [url=http://www.gunsamerica.com/guns/976400055.htm]Here's[/url] a "Pac West" lower. [img]http://www.gunsamerica.com/upload/976400055-6.jpg[/img] From what I can make out of the Pac West logo the two look alike. The first lower is obviously and A2 and the second one is an A1. I can't find the story between these two companies anywhere. Didn't one of the big names buy PWA? |
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Rock River Arms bought PWA out. RRA is in Illinois. Their early lowers were still marked RRA.
-Troy |
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That was it, RRA bought PWA. So is PWA of IL descended from Pac West Arms of WA?
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Yes. RRA's first couple hundred rifles were built on RRA-marked lowers, and they were selling RRA lowers at that time (late-98, early-99).
-Troy |
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RRA's first couple hundred rifles were built on [b]PWA[/b]-marked lowers, and they were selling [b]PWA[/b] lowers at that time (late-98, early-99). View Quote Is that correct or did I misinterpret? [bored kode] |
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Can you tell it's been a long day? Yes, that's what I meant. [BD]
-Troy |
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