Why do any modern guns have pounds of excess metal when all you need is a few ounces of steel in the barrel extension and bolt to contain even high pressure rounds like the 5.56?
It's surprising that so few gun designs take advantage of this fact. If anything, designs are trending heavier. Why aren't there lightweight designs out there that utilize this capability? Not only do designs like the M1 carbine with minimalistic receivers save weight, they save money too. Is it just due to greedy industry execs stifling designers to keep prices high?