Quoted:
Since the billet that used to mill "billet lower" were cast, then wouldn't it stand to reason that it's really no better than your cast lower? I'm talking pound for pound, with same spec, and not having additional thickness or strengthening beyond the Milspec.
So in that sense, forged lower would be stronger than billet lower, except that billet lower makes up for the difference by having additional strengthening.
So does anyone mill a billet that's forged? That'll probably yield the best receiver.
Not exactly,
The quality of a casting can vary greatly depending on a number of factors.
When you attempt to cast something like a Lower, the 2 big issues are:
- Getting the material to fill the mold evenly, with a complex mold like a Lower, it can be difficult to get the material to flow into the mold evenly and fill all areas consistently. Pouring/placing the material in the mold can easily result in trapped or entrained air which will result in varying thickness of the material.
- Getting the material to cool evenly and at a the desired rate. With material in a Lower Mold, thinner areas and areas closer to the outside of the mold will cool more quickly. The result is varying strength in the material, cooling at the wrong rate can make it brittle or weak.
This means if the casting is not done properly a Lower can be very prone to thin areas, and areas that are brittle or weak.
When you cast an Ingot or Billet it is easier to control the issues because you are pouring the material into a simple / open mold. As such you can get a more consistent and complete filling of the mold and a more consistent cooling rate.
Hopefully that makes sense!
"Capt Richardson"