When you need excellent components for your firearms that don't compromise quality, you need Rainier Arms. With a wide variety of Rainier Arms Gun Parts, Rainier Arms Rifle Parts, Rainier Arms AR15 Parts and more, you can totally outfit your favorite firearms with to make them as reliable, accurate, and sturdy as possible. Rifles barrels are one thing that Rainier Arms is particularly known for, as they make a wide variety of AR15 barrels in tons of the most popular calibers, like .300 AAC BLK, .223 Wylde, .308 Winchester, and more, so you can build a brand new AR from the ground up or start a caliber conversion easily. All of their parts are made to the highest standards, so whether you're putting together a new weekend plinker or you want to build a competition-grade firearm for use at big time events, you can count on Rainier Arms.
Essentially, yes, all Rainier Arms barrels should fit in mil-spec upper receivers. This is perfect if you are planning to switch to a new caliber, as you don't have to replace all of your components to make the switch. However, even though the barrel will fit into the upper receiver, you must make sure you have a lower receiver that is specifically rated for the new caliber. This means that if you want to switch to .308, the upper receiver and barrel won't function with a lower receiver designed for .223.
One of the reasons AR-platform firearms are so popular is because you can customize virtually any part yourself without needing to go to a gunsmith, and that includes the barrel. Taking apart and AR15 is fairly simple, and once you separate the receivers, you can easily take out the barrel and put in a new one.
When you need help gearing up and getting your firearms in the best shape possible, you can count on Rainier Arms and OpticsPlanet! We offer Free Shipping on most orders over $49, so you can save as much money as possible on your upgrades.