Originally Posted by bluez
Anytime you ahve a billet lower you are doing well
billet just means its milled out of a block of aluminum which is first cast into the block. forged means it was cast into the shape skipping the machining part.
with aluminum there is no structural difference in metals of the same grade when it comes to carving out of a block of aluminum or pouring into a mold.
what IS important is, is the lower made to milspec tolerances or better??
in a upper, if your machinists are very good and using new or very good condition cutting tools you can get very close tolerances from carving out of a billet of aluminum. this matters for uppers, for lowers long as it meets milspec it doesnt matter. all the accuracy of a AR15 is in the upper.