11-27-2017, 03:32 PM
Guys, the upper receiver is not a stressed part to contain the pressure event, the barrel extension, bolt, and barrel are.
Billet receivers made from 7075 T6 usually have more material on them as well.
Yes, it is true that forged 7075 T6 uppers have more density because of the forging process. They start with a plate of aluminum, then crush the shape of the receiver onto it basically.
Since the AR15 forged receiver is meant for lightweight, the wall thicknesses are about as low as you would want to go, especially for the M4 upper, which has very thin walls above the extension tunnel, unlike the original carry handle models with the fixed rear sight and protective "handle" for the original trigger charge handle prototypes.
When I look at the Seekins, Mega, LaRue, Precision Firearms, etc. billet receivers, they have added mass around the barrel extension tunnel, much more than the Mil-spec minimal dimensions for a forged upper.
Even with the skeltonized billet receivers like from 2A Armament, there was a guy who had a catastrophic malfunction with a faulty round of ammunition, and his receivers didn't fragment like a lot of forged receivers do.
The argument about forged strength vs billet strength has no real practical value in terms of pressure containment.
The added material offered by billet receivers does bring a practical value for someone building a rifle with a heavy bull barrel, comparable to the added strength from A2 uppers that Service Rifle shooters use.
The precision fit of a billet set also offers that solid feel of the gun that you just don't get with most forged receiver sets.
Billet receivers made from 7075 T6 usually have more material on them as well.
Yes, it is true that forged 7075 T6 uppers have more density because of the forging process. They start with a plate of aluminum, then crush the shape of the receiver onto it basically.
Since the AR15 forged receiver is meant for lightweight, the wall thicknesses are about as low as you would want to go, especially for the M4 upper, which has very thin walls above the extension tunnel, unlike the original carry handle models with the fixed rear sight and protective "handle" for the original trigger charge handle prototypes.
When I look at the Seekins, Mega, LaRue, Precision Firearms, etc. billet receivers, they have added mass around the barrel extension tunnel, much more than the Mil-spec minimal dimensions for a forged upper.
Even with the skeltonized billet receivers like from 2A Armament, there was a guy who had a catastrophic malfunction with a faulty round of ammunition, and his receivers didn't fragment like a lot of forged receivers do.
The argument about forged strength vs billet strength has no real practical value in terms of pressure containment.
The added material offered by billet receivers does bring a practical value for someone building a rifle with a heavy bull barrel, comparable to the added strength from A2 uppers that Service Rifle shooters use.
The precision fit of a billet set also offers that solid feel of the gun that you just don't get with most forged receiver sets.
NRA Basic, Pistol, Rifle, Shotgun, RSO
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com