Ok i am looking into building my 4th  AR.. beeen looking at eather a billet upper/lower from LaRue, or a Billet upper from Alexamder Arms. Now  my question is.. what is different from a Billet upper/lower and a Reg upper and lower?

I think the differance is that the billet upper or lower is cut from a solid block of metal with a cnc machine, rather than a upper or lower that is cast, meaning that it is melted metal poured into a mold. The quality would i guess depend on the quality of machine making the product. Which one is better? your guess is good as mine.

Most uppers/lowers are forged, not cast. A forged part is basically hammered into shape from a piece of metal.

yeah thats right forged my mistake thats why i put the i think at the at the begining of my answer, i was right about the billet part though right

thank yall for the help, im going to go with the Billet all the way.. even though its going to be more expensive.

My understanding is that when dealing with a quality forged receiver or with a billet machined from a quality starting piece, the only difference is that the billet receiver will look prettier, but not be any stronger.

I thought most billet uppers were thicker walled, meaning stronger.  Am I wrong?

i was  just told by a gunsmith that its  Ok to get a billet  upper. but  gota be  safe when buying the lowers.. most  of them are not to the right  spec in the mag wells that's what he was saying

Have you seen the new Denny's Billet lower?  It's SOOOOO sexy!





http://global-tactical.com/dennysgunsbilletlowerreceiver.aspx
 

Have him define "most" when you talk to him again. If there is a receiver out of spec, it is due to the machining process on the particular lower in question, not the fact that one would be billet over forged.

Forged lowers are more plentiful, billet lowers are cleaner looking and require a bit more machining, hence the higher price. Anodizing is what makes them both stronger.
It all comes down to buyer preference. I have both. I like both.

Forged is the stronger of the two as in a forged part the material is compressed in the massive amount of force required to shape it. Billet parts try to make up for this by leaving the part thicker where possible.

Dennys lower is a beautiful, excellent, awesome machined billet lower receiver. They are made by the superior craftsmen at Tactical Innovations in Bonners Ferry, ID.

Craig's company (Tactical Innovations) does one Hell of a job produciing forged AND billet lowers that are works of guncrafters art.

Forged, any day, will be stronger on a lower. Why?  The weakest part is the buffer tube ring at the rear of the lower.  Here, the forged lower has a flowed grain structure optimized for the area.  

Hogged out of bar stock, the grain of the metal is like that of straight-grained wood.  Entirely wrong for the part.  With good quality 7075 aluminum, you can get away with it.  But how many are actual Kaiser/ALCOA/Renyolds with Certified Mill Test Reports?  And how do you know the grain direction? You are at the mercy of the machinist who may or may not know about aluminum microstructure.

Now let us look at the typical Mill Test Report for aluminum.  Firstly, there is the chemical analysis.  This tells us the alloy.  Then there is the temper designation.  We want T6.  No need in having to send it out for heat treat as then more testing.  Then we have tensile testing.  

Now for the fun part.  Tensile testing.  This part of the MTR will have at least two, if not three tensile specimen axes.  Not the Paul Bunyon tree felling implement but the direction in which the samples are loaded.  There will be specified minimums, yield point, enlongation and ultimate tensile strengths reported.  For sheet products, there is typically only two tensile coupons and a shear but for plate/bar, there can be three tensile tests.  Since the lower is subjected to triaxial stress with associated moments, it would be a good idea to insist on knowing these properties.

But in a forging?  Part of the quality process is complete tensile testing of the rough forging and sample coupons have been taken from a representative part.

Since non-destructive testing on aluminum is limited to RT/UT/PT and all but PT are specialized  practices, buying a  receiver hogged out of bar/plate is a gamble.  I would suggest a copy of the mill test report.

And despite the over misuse of the term "billet". I continue to call these plate machinings.  Why not billet?  Because a billet is a raw mill product without any wrought processing.  Billets are technically CASTINGS and not what the machine shop or even forging plant uses as raw material.  Forgings are made from BAR STOCK which is a wrouught product form.

Great info, thanks.  Very enlightening.  All the more reason to be stoked on my kaiser lower.

It's a gimmick....

Rather than forging the upper/lower into it's exterior shape, the 'billet' products consist of a forged block that is milled into the shape of a reciever....

CASTING is an entirely different process that is rarely used to produce AR recievers these days....

The 'Normal' way is to forge it into shape, then mill out the internals.....

Here is where people hear something, then think it means something else. Anodizing does NOTHING to strength.  It is brittle, being a form of aluminum oxide not unlike that common abrasive on sandpaper.  It is flat, solid ceramic made from the aluminum itself so it has great adhesion.

In the M16 series, the upper only holds the pieces of the rifle together and forms a guide for the bolt carrier.  Because the only real sliding force contact is the carrier key's reaction to bolt locking/unlocking torque, this is the only real wear area.  The sliding forces of the carrier are very low, representing only the misalignment of the carrier.  Since the carrier key slot is protected from dirt, this causes the carrier's rails to exhibit the greatest wear even though steel is much harder than aluminum.  The anodization polishes the rails slowly.  In proper treated uppers, a layer of moly disulfide dry film lube keeps this wear minimal.

In fact, hard anodization can form surface crack propagation, lowering fatigue life.  But this is not significant in the M16 series as there is sufficient ductility and the receivers are subjected to very low cyclic stress.  

Hard anodization is a durable finish, resistant to most abrasion from normal "sling type" wear.  But being brittle, impact with hard surfaces will cause failure.  The military refinishes with moly disulfide dry film lubricant, all over.

Dang Keith_J, you are on a roll.  Thanks again.