Newb question:

Other than looks and weight, why aren't 16" carbines made with a lightweight, low-profile gas block at the end of the handguards and the FSB out at the end of an M4 barrel to maximize sight radius?

Thanks.

Perhaps the development folks at the U.S. Army's Rock Island Arsenal can better answer that question then a bunch of people on this site that had absolutely nothing to do with the design of the M4 system.

Maybe because there's no such thing as 16" M4

I have pretty limited AR knowledge, but if that statement is true, then why does CMMG sell the following:

"Chrome Lined MOD4 16"Barrel

New Production Mil-Spec 16" Chrome Lined 5.56 chambered M4 barrel. 4150 steel. 1/7 twist?"

I looked at the dissipator setup, and I may be misunderstanding it, but those uppers had longer handguards that increased the weight substantially (it seemed.)  So, what I'm trying to see is if you could get the same benefit of increased sight radius (assuming one didn't want to install a bayonet), by just pushing the FSB to the front and maintaining the gas system with a low profile gas block?

Thanks again.

Thanks Troy.