11-27-2017, 03:08 PM
Eoch - Firstly, welcome to the Clan, from the Great Nation of Texas!
You will find a lot of discussion across this forum regarding billet vs forged.
The core is this: a billet is just a block of metal ( in this case aluminum ) that someone can load into a CNC machne and create fancy looking uppers and lowers. The advantage is that this methodology does lend itself to very intricate patterns and that there is absolute repeatability in this machined result. The issue is that there are metalurgical anomolies within any "billet" material which "could" cause failures IF something goes wrong.
With a forged part, a "near melting temperature" heated block of material ( in this case aluminum ) is set inside a die set and those dies are "slammed" together with extremely high level of force one or more times to form a particular shape. Then that result is machined to form the inside passages and the result is a usable upper or lower. The advantages of forging is that this "slamming" process forces the molecular structure into a "grained" pattern which results in a MUCH stronger material that is completely void of any metalurgical anomolies that "could" cause failures if something goes wrong. A key example is rifle barrels - have you ever seen a billet barrel? NO, all the better ones start out as hammer forged to get the greatest yield strength.
Most of the time, the difference does not matter. But, if a case ruptures on ignition, the strength of the material around that chamber is all that is between a 50,000+ psi ( think IED! ) and your head.
I have built a LOT of AR's / MSR's and will not use a billet upper or lower. Yes, I do have to do some extra machining to get the best fit, but, to me it is well worth the trouble.
You will find a lot of discussion across this forum regarding billet vs forged.
The core is this: a billet is just a block of metal ( in this case aluminum ) that someone can load into a CNC machne and create fancy looking uppers and lowers. The advantage is that this methodology does lend itself to very intricate patterns and that there is absolute repeatability in this machined result. The issue is that there are metalurgical anomolies within any "billet" material which "could" cause failures IF something goes wrong.
With a forged part, a "near melting temperature" heated block of material ( in this case aluminum ) is set inside a die set and those dies are "slammed" together with extremely high level of force one or more times to form a particular shape. Then that result is machined to form the inside passages and the result is a usable upper or lower. The advantages of forging is that this "slamming" process forces the molecular structure into a "grained" pattern which results in a MUCH stronger material that is completely void of any metalurgical anomolies that "could" cause failures if something goes wrong. A key example is rifle barrels - have you ever seen a billet barrel? NO, all the better ones start out as hammer forged to get the greatest yield strength.
Most of the time, the difference does not matter. But, if a case ruptures on ignition, the strength of the material around that chamber is all that is between a 50,000+ psi ( think IED! ) and your head.
I have built a LOT of AR's / MSR's and will not use a billet upper or lower. Yes, I do have to do some extra machining to get the best fit, but, to me it is well worth the trouble.