Opinions on billet uppers and lowers.

[hags]

Boutique parts for high end niche market or quality made parts to last a lifetime?
What are your thoughts and opinions?

[Alpha Sierra]

The Highpower guys have demonstrated time and again that any ol forged upper and lower within spec is more than enough to make super accurate ARs.

[DRich]

I think it's simply another quality option available to consumers. Same reason Baskin Robbins has 31 flavors. I don't think they perform any better or worse than a good forged unit, but it's nice to have variety in the market. I've thought about buying them solely for the aesthetics.

[C4IGrant]

The problem with upper receiver forgings is that the rail is almost impossible to get square and true. For mounting magnified optics, this is a must in my book.

The billet lowers just look nicer than anything else IMHO.



C4

[bigbore]

The Highpower guys have demonstrated time and again that any ol forged upper and lower within spec is more than enough to make super accurate ARs.

All a billet upper/lower gets the end user is a lighter wallet.

[olds442tyguy]

Billet uppers are more precise and have less internal stress than a forging, but forgings have proven themselves beyond a doubt.

Either way it probably doesn't matter, but the Vltor MUR is damn sexy looking.

[Alpha Sierra]

Billet uppers are more precise and have less internal stress than a forging

The receivers in an AR are not stressed components as they are in other rifles (bolt guns, M14), therefore less internal stresses are a moot point.

And since the upper is not what determines barrel to bolt luckup, any higher level of precision is not going to help.

I am not a machinist, but I do have more than some passing knowledge in the technology. Material choice has little to do with the precision of machining. There factors far more important than material choice. Fixturing, selection of datum planes and datum cuts, machine precision, feed rates, spindle speed, insert or end mill choice, and many other factors.

[Alpha Sierra]

The problem with upper receiver forgings is that the rail is almost impossible to get square and true.

I find that difficult to understand given my knowledge of fixturing and tooling.

[hags]

Billet uppers are more precise and have less internal stress than a forging, but forgings have proven themselves beyond a doubt.

Either way it probably doesn't matter, but the Vltor MUR is damn sexy looking.

I don't know of anything that would make a billet inherently more "precise". Just like it's forged or cast counterparts that would depend on the quality of the machining done to it.
They do tend to be better finished than most though.

[olds442tyguy]

Not all of a forged AR upper is machined. IE; some areas are left as forged, which can leave/create areas of difference that may or may not be decisive in performance.

A billet is 100% machined in every dimension, meaning they are much more "precise".

The receivers in an AR are not stressed components as they are in other rifles (bolt guns, M14), therefore less internal stresses are a moot point.

Internal stress as in stress in the material, not external stress on the receiver.

Like I said though, pound for pound it's really no concern.