This question was asked by a member of AK-47 dot com. I was one who decided to respond, and decided to paste it here for you to read, and maybe add to the topic. The topic is at AK-47 dot com, but if you feel more needs to be said, I would be willing to copy and paste your responses in that forum. Thanks in advance:).......................................................................................................................................
Here is an example, Bushmaster uses the same forged upper and lower ingots for their semi autos, as they use for their fully autos. The foundries supplying them use very heavy duty hydraulic hammer forging machines, which are said to be extreme The upper die will give half the receivers shape, while the lower die will give the other half shape. I spoke to a Colt Representative that was at a Firearms Rep show we were holding. He had worked his way up, he started as a factory employee, and ended up as a Company Rep. I was very interested in some of the details of their weapons, so I did ask about their rifles (the AR-15's). He informed me that the foundries that supplied them with the ingots were so good, that almost no machining is done to the exterior surface. Sure you will see the trimming where the upper and lower forging dies meet, but for the most part, the exterior finish is what the dies leave behind, including those raised letters one usually sees near the rear sight area of an A2 upper. The two dimples that one finds where the safety/selecter area is of an AR/M16, are also formed during the forging process.
I was also told by another person (a Bushmaster Representative), that the dies are usually owned by the AR companies (example: Bushmaster and Colt both own their own dies). They do wear and they sometimes need work, maybe even need replacement. The foundries and the receiving AR manufactureres both keep an eye out for die problems. When unacceptable wear or other problems occur with the dies, the AR companies that own them are responsible for the costs involved in their repair or replacement. With smaller AR companies, they may not even own their own dies, opting to buy the ingots made with the foundry owned dies. By doing it this way, the AR manufacturer avoids having to service or replace the dies, but they will pay more per ingot, since the foundry will get stuck with any service or replacement of the dies.
Bushmaster is one of the companies that make real M16's, as well as civilian AR-15's. They don't request second quality forgings, they don't need to. Civilian or Government, they make sure they get the profit they need. Actually, you as a civilian pay more for a civilian AR-15 then what the military pays for their M16's and M4's. The M16/AR manufacturers love Government contracts because of the volume numbers, but they do get less per gun with a Government contract. Right now, Colt charges the Government over $500 for a select fire M4 Carbine. A civilian gun distributor may pay $700++ for a civilian semi auto Colt M4. Bushmaster & Colt make more money per civilian gun, then they make per Government gun. The Gov offers two big things for these types of companies. They get big money (in volume sales), and they get a major feather in their caps (because they can use that feather for future promotion of their products). When it's time for Bushmaster to make their guns, M16's or AR's, they grab the forged ingots from the same pile. There are no differences in the forged ingots used by Bushmaster for making M16's or their semi auto AR-15's. The differences are only made when these forgings go through their final machining for either semi auto, or select fire, and even then, only in following the legal specifications required for legal sale of the weapons. Bushmaster actually improves their products by doing it this way. They train their employees with only one method, and by that I mean the correct way. It's keeps them on top of the game for when they are called to meet GOV Specs on their M16 series. You see, it's not really the price of the forged ingot that is so prohibitive for the AR manufacturers. The added costs really come more from the processes needed to complete these ingots into a finished product, thats where most of the costs will come from during the manufacturing of forged components.
Many metalurgical methods have been designed to duplicate the qualities of a good metal, well stress relieved, and well heat treated forging. Most times its because of cost. They are trying to duplicate the qualities of a forged product, without the costs involved in a true forged product. Forgings usually require so much more machining than a casting, and that is ONE of the biggest reasons a forged product costs more to make. The hydraulic forging machines used to make such a smallish piece like an AR receiver, are huge, and very costly. Even the big boys like Colt, and medium size guys like Bushmaster, get their ingots from foundries, (rather than setting up in house foundries). Even foundries look for ways of cutting costs, and not only for themselves, but also for their customers. The new methods are usually designed to, not only possibly lower their own costs, but also cut milling time and possibly other facets of operation for their customers. This might mean their AR manufacturing customer may be able to make more finished product in shorter time. It may mean they can let go of some of their labor force, but still increase production. In other words, possibly make more profit.
The Ruger company makes their "P" series pistols using barrels that are made using the investment cast method! One might say "WHAT"! Yes, they really do investment cast their "P" series barrels, BUT.....then put them through a compression process to give them the QUALITIES of a true forging. This is not made up, this is the way they themselves state it. So you see, forging has reached an ultimate level, and many folks just want that level in their products. Today, with hydraulic die forging machines and better understanding of stress relieving, forging is still the method to beat. CNC milling machines have made the use of dozens of milling stations, previously used for finishing forgings, obsolete.
One or two CNC milling machines can usually do the work of all the old machines. That all amounts to less cost for a forged product, but you can still buy a cast lower AR-15 receiver for less money then its forged counterpart. Why, because overall the forged product still costs a bit more to manufacture, but worth it in my opinion Work's okay for the militarys M16, it will work just fine for my semi auto Bushmaster Go with what you want, but if you want to keep it a bit more faithful, buy the old proven method the Government still gets with their M16's/M4's, that being the forged upper and lower receiver IMO