Guy comes in our shop last week to talk to me about his M4. He takes a DPMS A1M4 out. It clearly has cast receivers. The way we were talking so casually, I thought he may have bought it at our shop before I worked there or something, but we dont carry DPMS? So I asked. He seemed to have felt bad when he said said no, and that he had gotten it at one of our competitors. I told him it was no big deal to me and that I would be happy to help him now. He told me about some things he liked about the gun, and some he didnt. All I did that day was change his A1 apperature to an A2, and gave him a price to take everything off his upper and put it on a stripped flat top upper.

Week goes by and he comes in to see me again. He tells me that there had been some disaster as he picked up his rifle bag to come in to the shop and trade uppers. The bag was unzipped or something and as soon as he picked it up, the gun fell out and hit the floor about 2 feet below. It landed on the stock and cracked the lower where the receiver extension screws into the receiver! He was pretty upset and started asking about if it could be repaired or what it would cost for a new lower. Thats all the bad news.

Now for the good news. I told the guy that first thing we should do is call DPMS and see what they say. I said if they do replace it, ask if he could pay extra to have it upgraded to a forged receiver. I then looked in their newest catalog and read that DPMS offers no written warrantee on their products. Yikes! There was something in there about they knew their responsibility to the customer etc, etc, but I was nervous for the guy. We called DPMS and told them what happend. Guy we spoke to (cant remember his name) was very accomidating. He basically asked me to return the broken receiver and send them a copy of our FFL. They are replacing the cracked cast receiver with a new forged one. He said they discontinued their cast revceivers all together and only do forged now. Thats good news. So, all this guy has to do is pay us to ship it back to DPMS (had he bought it from our shop, we would have paid shipping under our warantee), and the $5 background check when the new one comes in. He'll have to wait about 2 weeks for them to turn it around, but all in all, I thought that was very good of DPMS.

Here's a couple pictures of the cracked cast receiver after I stripped it of parts and before I sent it off.

Quoted: Thats good they didnt charge an arm and a leg to replace... Does anyone still do cast recievers anymore?  I dont know how they can be affordable to produce if they break so damn easy.

Essential Arms is back in business selling their own branded cast receivers. I have never heard of an EA cast receiver breaking. I recently picked up a pre ban one pretty cheap (NY and all) and am curious to build it up and see how it does. Nice looking receiver despite being cast.

Lots of companies have that "we aint's sayin' nothin'" warranty policy, I guess for liability reasons. I think Ruger is similarly silent on their warranty, I wouldn't worry about DPMS taking care of problems products in any event.

I've almost never heard of a AR receiver breaking, but the very few times I have heard it, they have all been cast receivers. That being said, I have seen a few Essential cast receivers, and hear they are likely among the best of the cast ones. Speaking of Ruger, I swear I read that Ruger did some of Essential's receivers for them way back when. I think I read that from Chuck who used to post here often, but only posts infrequently in recent years.

Ruger did/does do some kind of revolutionary casting work, I think. I think they made recievers for someone, not sure if it was EA, will try to look it up tonight and supply that info tomorrow am.

$5 is what the Florida Dept of Law Enforcement charges our shop to do the check.

Thanks for posting this, Neil.  Hopefully some of the "I've never heard of a cast lower breaking" folks will get to read this.

We all know that, under "normal" civilian circumstances, a cast lower shouldn't have any problems.  In real life, guns usually get some abuse, either through use or by accident, as in this case.  Cast receivers are brittle and prone to cracking and/or shattering when subjected to impacts, which is exactly what happened here.

-Troy

Quoted: Thanks for posting this, Neil.  Hopefully some of the "I've never heard of a cast lower breaking" folks will get to read this. We all know that, under "normal" civilian circumstances, a cast lower shouldn't have any problems.  In real life, guns usually get some abuse, either through use or by accident, as in this case.  Cast receivers are brittle and prone to cracking and/or shattering when subjected to impacts, which is exactly what happened here. -Troy

Troy,

My understanding is that casting is just not nearly as forgiving as a forging.  While it is possible to make a proper, functional cast reciever, I doubt it could be done at any significant cost savings over a forging.  I would only trust a cast aluminum part from a high end caster like Ruger.

It seems the likelyhood of getting a fatal flaw in the part is far, far higher with casting.

Quoted: Troy, My understanding is that casting is just not nearly as forgiving as a forging.

"Forgiving" isn't really the right term.  Cast parts can't withstand anywhere close to the amount of impact force or torsion as a forged part.

While it is possible to make a proper, functional cast reciever, I doubt it could be done at any significant cost savings over a forging.  I would only trust a cast aluminum part from a high end caster like Ruger.

It is STILL substantially cheaper to make a cast lower, as the mold for a cast part can be much more detailed, requiring much less finish machining than a solid raw forging.  That's why it was done in the first place.  But for a machine shop that is already set up with the equipment and programming to machine raw forgings into usable receivers, cranking out more of them isn't all that hard, and that's what's led to the explosion in AR "brands" and the high availability of quality forged lowers at low prices.  Those low prices and good availability have so lowered the demand for cast lowers that they are virtually obsolete these days.

-Troy

Quoted: Basic answer for a basic question: What is casting v forging? Using a preformed cast into which is poured steel = casting? Molding and manipulating moltened/soft steel = forging? TIA docgary

Well, in this case, the metal isn't steel, but aluminum alloys (different alloys for forgings vs. castings).  A casting is exactly what you describe: pouring molten metal into a mold.  This will result in voids in the metal and a fairly "loose" molecular structure.  The advantages are that casting is fast, and that the molds can be much more detailed, reducing the amount of finish-machining that is required to turn the raw casting into a finished, usable part.

A forging is a piece of metal that's been placed in between dies (similar to a mold) and then the metal is forced to assume the shape of the die via a hydraulic hammer pounding the dies together.  This results in a part that has the "grain" of the metal formed into the basic shape of the part, and "closes" the molecular structure of the metal, making it far stronger.  The raw forging is a solid chunk of metal with the outward shape of the final product, and must be finish-machined into a usable product.

-Troy

The lower came in early this week. I put it back together for the guy, called him, and he came to pick it up the same day. Good show for DPMS. The lower looked a lot better than the one it had replaced. His upper is still cast, as is his front sight base. He is still considering buying a RRA flat top from us. If he does, he'll have a new forged uper and lower. I may have some take off front sights I might try on the barrel. If one of them fits, I'll trade him up to that as well. I've almost never found a second front sight that matches the pin grooves in the barrel though.