Does the AR have a rival in today's market? As near as I can tell, it is pretty much peerless.
A big plus for the AR is of course the economy and the modularity. You can get a decent rifle from PSA for $400 and change anything on it to meet your needs because the rifle is easy to work on and the market is expansive. Nothing else on the market competes with it in this regard. Plenty of other options have attempted to offer the modularity of the AR, but have failed. The XCR, FN SCAR, the ACR, and the SIG MCX have all been marketed as modular carbines but have failed to gain support of the AR because they have failed to support their designs. Caliber conversions end up being scarce, and expensive when found, and in the end, quick change barrels don't add a lot of utility over switching out an upper receiver on an AR. And that is what appeals to a lot of people with the AR design. You just have options with the AR that you don't have anywhere else. From braced pistols and pistol caliber carbines to long range precision rifles, in a myriad of calibers and configurations, with the AR, your imagination is truly the only limit. And while you can go super expensive, the market is such that rifles and parts are cheap right now, and the design is such that someone with a bench and a few tools can build or modify at their heart's content in their own garage or basement. Very little else on the market is as approachable in this regard as the AR.
As an example; you can pay $3000 for a FN17S, then dump another $1500 into improved forearms and buttstocks, triggers and controls, then pay $40 for a magazine, or you can build an Aero Precision M5 with the furniture you want for $1100, pay $20 a magazine, and have a rifle that is functionally identical to the 17s in 99.99% of any situations you're going to face, even in the Thunderdome. If you want to add barrel length or a heavier barrel or change calibers on the FN, your options are limited, scarce, and expensive. Spare barrel assemblies run over $1100 in Brownells, and you're limited to 5.56 and 7.62 NATO in a few different lengths. You can 1/2 as much building a pretty good complete upper receiver in any number of different barrel lengths and configurations--6.5 Creed, .500 Auto Max, .338 Federal--whatever you want. Or you can spend 1/4 as much on a new barrel for your existing rifle and install it yourself while watching cartoons with your kids.
It used to be the little poodle shooter that crapped where it ate, but since I've owned ARs, they've really grown on me. My ARs have been the most reliable, easy to own and operate firearms in my collection. I use little else anymore. Whatever I need done, from hunting to defense, my ARs will accommodate in a platform that is accurate, comfortable, and simply fun to use. The AR is America's Rifle. Americans own over 15 million ARs, making it the most popular rifle design in the US. It has no peers and no rivals. It is alone at the top of the heap because it does things no other rifle does at a price that makes it accessible to working men.
And now for the obligatory gun porn, I present, my ARs. There are many like it, but these ones are mine.
Colt 6960CCU with SIG Romeo 7 and Juliet 4 magnifier on FTS, and its big brother Aero Precision M5 with Trijicon TA-11J ACOG.
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