I am looking to buy my first AR. The biggest dilemma that is facing me is the choice of caliber. Obviously, the main stream choice is the 5.56/.223 but I am really interested in the .300 Blackout because of the larger size of the round and the perceived greater stopping power. The AR I am drawn to the most is the Smith & Wesson M&P 15 Sport because of the price and I am a S&W fan. That rifle compared to an AR in .300 is a difference of around $1,000 from what I have been able to find. My question is, do you think that it is worth the extra money for the larger round or should I go with the cheaper option? I plan on using the rifle for home defense and of course range time. Do you think that I should buy a rifle in 5.56 and then possibly at a later time purchase a .300 upper? I am not sure if this will impact your suggestion but I also plan on putting a suppressor on my rifle at some point. Thank you for your help.
Short answer: No. Let me explain . . .
We’ve talked at great length about 300 AAC Blackout here at TTAG and as some of you can tell, I’m a bit of a fanboy. But while the round fills many roles (subsonic functioning, short barrel performance, interchangability of parts and cases) it’s not the best choice for a new AR-15 owner.
The true power in the 300 AAC Blackout round is that the only difference between a 300 BLK rifle and a 5.56 NATO rifle is the barrel. Everything else, including the bolt, remains the same. This is especially important for existing AR-15 owners, as they already have spare magazines and parts for their existing rifle, so making the switch to 300 BLK is effortless.
For new shooters, however, you run into the ammunition supply issue immediately. While there are a lot more manufacturers of 300 BLK ammunition than there were this time last year, they’re all out of stock. And the few stores that have the ammo on their shelves are asking around $1.50/round. I’d think twice about paying that much for .308 Winchester, let alone 300 BLK.
The best option is to buy a 5.56 caliber AR-15 and get a replacement upper receiver down the road. Especially if you don’t have a silencer ready to go for the rifle, there’s no point in spending money on the more expensive ammunition right away. Get the rifle, and six months after you send away for the paperwork, drop some more cash on an upper. In the meantime, you can take advantage of the slump in AR-15 sales to pick up a new gun for a song and a dance. Relatively to the last few months, that is.