The .300 Blackout is based off of a shortened 5.56x45mm case that is necked to .30 caliber. For AR-15 platform rifles and pistols it only requires changing the barrel to go from 5.56 to .300 Blackout. The Blackout's main purpose is to be used at subsonic velocities in suppressed firearms. Many bolt action and single shot rifles are now being produced in this caliber as well.
* Starline Brass does not sell any loaded ammunition. What you are purchasing are brass cases only and will need to be loaded into ammunition in order to be fired from a firearm.
Fantastic brass, and you really cannot beat the price for NEW 300 bo brass. I ordered 1k the first time around, and I liked it so much that I ordered another 1k. If you can catch it in stock, you better get it before it gets gone, because it goes fast.
Howard Helvie Oakland, OR
February 27, 2021
This was outstanding brass and great service. I have been reloading for 45 years and this is by far the BEST value in the business. Virtually no prep work needed, no bad cases. If you only made 257 Roberts and 300 Win Mag I would never buy anywhere else. (hint hint)
Gary Raynor FEDERALSBURG, MD
January 23, 2021
My only regret was I didn't buy more when it was available. Every piece was perfect.
Robert R Buschbom Waterloo,
December 04, 2020
Received 1,000 box and looked for culls. Found none. All case mouths were very close and only needed a quick mandrel check. Primer pockets were square so I took maybe 3-4 grains of brass from the 1,000 instead of the usual 20 from other brands. Flash holes don't appear to have burrs, just need to chamfer case mouth. Starline has maintained their quality over the 40 years I have been using them. If I wasn't picky about match prepping my brass would load right out of the box and probably not notice a difference. Made in USA, thanks folks.
Paul Hanson Sheboygan Falls, WI
August 15, 2020
Just received my first order with Starline Brass & I am very pleased. Shipped in good condition and in a very timely manner at a price point & availability that is very acceptable. Brass was found to be very consistent, primers and rounds loaded well, rounds all functioned with zero failures. Made in the USA this brass and the people who serve you will not disappoint. Thanks Starline for providing consistent affordable and available brass that makes my firearm very happy.....
Joe Leighty Scottdale, Pennsylvania
January 05, 2018
I have bought Starline pistol brass for years and have been very pleased. When they started making rifle brass I couldn't wait. The 300 AAC BO brass is wonderful! They are consistent in overall length, neck diameter, weight and primer tightness. I couldn't ask for more.
Joseph Leighty Scottdale, Pennsylvania
December 09, 2017
I'm never disappointed in Starline brass and I am so glad they finally got into rifle brass. I recently bought the 300 AAC Blackout brass and began to work with it. Without exception it could be loaded right out of the bag. I have found no deformed case mouths yet and the length is remarkably good. I have to do something to the cases or I don't feel I prepared them so I have been reaming the inside of the flashholes to make sure they are uniform and I chamfered the case mouths though I don't think the outside is in need of that operation. Primer seating feels very uniform and tight enough. These are great cases and I plan to buy more when the time comes. Thanks Starline for another great product.