300 Blackout Brass for Reloading *

300 Blackout Brass for Reloading – Cleaned, Sorted, and Ready for Your Bench

Reloading the 300 AAC Blackout requires brass that is consistent, reliable, and properly processed, especially if you’re feeding a semi-auto platform like the AR-15. At US Reloading Supply, our 300 Blackout reloading brass is professionally cleaned, inspected, and hand-sorted to ensure you receive high-quality cases suitable for accurate, safe, and repeatable reloads. Each batch is processed to eliminate damaged, crushed, or excessively worn cases, giving you a dependable supply of once-fired brass that saves time at the bench and improves your overall loading experience.

Our 300 BLK brass is sourced from once-fired, name-brand ammunition and goes through multiple stages of quality control. Cases are washed, tumbled, and polished for a clean surface that makes defects easier to spot. They are then sorted by body diameter, headstamp consistency, and case length, helping ensure uniformity from one load to the next. While all reloading requires proper inspection, trimming, and chamfering, starting with a high-quality batch of brass significantly reduces prep time and helps ensure safe chambering and reliable cycling.

300 AAC Blackout is a versatile cartridge that performs well in both supersonic and subsonic configurations. Because brass lengths can vary depending on firearm type and original manufacturer, we recommend checking every case for proper trim length, typically around 1.368 inches with a maximum around 1.368–1.373 depending on your load data and chamber. Using a quality case trimmer, calipers, and deburring tools ensures your reloads meet SAAMI specifications and cycle smoothly in both bolt-action and gas-operated platforms.

Whether you’re loading 110-gr supersonic rounds for hunting or 220-gr subsonic ammo for suppressed shooting, quality brass is one of the most important foundations of accurate ammunition. Our 300 BLK brass is priced competitively, packaged securely, and ships quickly—offering reloaders a dependable source of components without long delays or inflated prices. If you’re looking for affordable, reliable once-fired 300 Blackout brass, you’ve come to the right place.

Q: Do I need to resize and trim 300 Blackout brass before loading?

Yes. Even with sorted brass, you should always full-length resize and check trim length. Most reloaders trim 300 BLK brass to around 1.368 inches for reliable chambering.

Q: Can I convert 5.56 or .223 brass into 300 Blackout?

You can, but it requires cutting, forming, resizing, and trimming. Using pre-sorted once-fired 300 BLK brass saves significant prep time and typically results in better consistency for reloaders.

Q: Will this brass work for both supersonic and subsonic loads?

Absolutely. Properly processed 300 Blackout brass is suitable for both supersonic and subsonic ammunition, provided you follow safe load data and inspect cases carefully.

Q: Are mixed headstamps okay for 300 BLK reloading?

Yes, mixed headstamps are common with once-fired brass, but all cases should be checked for length and resized. Our sorting process improves uniformity, but always follow your load manual.

Q: What platforms will this brass work in?

300 Blackout brass works in AR-15 pistols/rifles, bolt-action rifles, and single-shot platforms. Always confirm headspace and cycle testing when working up new loads.