Originally Posted by winds-of-change
I'm new to guns and learning. I now see what a lower receiver is. What makes them different? Just looks or do they offer different sorts of shooting? Please be patient, I am very new to guns.
All lower receivers perform four basic functions: accept and hold a magazine, accept the trigger group, provide a pistol grip mounting and secure the stock...5 if you count the pivot and takedown pins...
That being said differences exist in the individual internal components as well as the fit and finish, and manufacturing methods, of the lower itself. JD does an excellent job of recapping the different types of lowers in one of the stickies in the AR thread, bottomline is stay away from the ones Cletus made from old soup cans...
So to answer your questions...the type of manufacturing and the quality of the materials used, including the finish, differentiate one lower from the other. Lower quality lowers may suffer from out of alignment issues, poorly drilled holes, machine marks, etc. Not enough to make them inoperable mind you just a little more difficult to work with. Lowers can be, in order of price; cast $, forged $$ or billet $$$$.
For the second part of your question...yes different shooting situations may require a different lower build, especially with the trigger. More precise, longer range shooting would benefit from a two stage trigger...everyday SHTF situations are fine with a standard trigger setup. Triggers are to some like Moby Dick to Ahab...they are on a life quest to find the "one," fortunately there are hundreds available to choose from. Point is, I guess, is that a stripped lower is an open format that the builder can assemble in most any way that suits him/her.
Hope this helps...I would recommend skimming through the stickies in the AR sections...loads of good info there if you're curious.