Lighter Carbines and short magazine capacity?
At first thought many might think that to be a stupid thing to do, but for anyone that has taken a carbine course, lighter firearms don’t wear down an operator the way a heavy one does. For all of the people that are bench rest shooters, a heavy AR15 barrel is something they want, but in a real fight, the difference between sub-moa and 4 MOA is pretty much a none issue. I have never shot an AR15 that did worse than 2 MOA and most of them were about 1.5 MOA or better. Rifle slings can make a bigger difference in comfort also so research that before you alter your firearm too much.
Once you have to get down in the dirt and fire from behind cover, you can really feel how well your firearms balance is. If the stock doesn’t fit you right it can royally suck to shoot proficiently. Magpul pmags are the best gun magazines I have ever used for my AR15’s but I have been using 20rd magazines more and more because of the balance it gives me with my firearms. Sure I’ll use the 30rd magazines if I really need to, but for urban environments gun magazine capacity over 15rds is good enough for anything but a zombie attack.