Uppers and Lowers and endless modifications, what’s the answer?
The simple answer is get more guns. The real problem I see with many people that tinker too much with firearms is that they can really mess stuff up. I remember seeing this with guys that overly modified their 1911s and put springs in the guns that they should not have and they ended up with an accurate POS. I don’t know how many times i’ve say behind a guy on the firing line that continuously informed me that his firearm was reliable but I’d watch them clear malfunctions all day and they would just blame the ammunition.
In my opinion, that is like watching a guy put tires on a car that are not the same size and saying the only reason he crashed the car was because when he made the wide turn the tires that were not uniform made him loose control. Well, stop messing around so much with your AR15 lower receivers and your AR15 upper receivers and make sure that once you get something that is reliable, stop screwing around with triggers and springs. You are better off with multiple firearms that do different things than trying to push a firearm to do everything. There is a trade off between reliability and accuracy and rarely does a firearm do both for very long.