So I have an idea, you take a plug made of glass that has been modeled in dimensions of buffer tube threading, fire control pocket, holes etc, then you pour steel/aluminum around it, having the proper dimensions to it, then after the customer buys the lower and uses some sodium hydroxide (drain cleaner) to dissolve the glass plug, creating a ready to use lower.

As I understand it, the melting point of the glass is higher than steel/aluminum so the plug will not melt, I assume the only issue here would be the shrinkage from the metal contracting as it cools?

Any unforeseen issues with this idea?

I assume the ATF will give it a no go because they are dicks?