Buy Lapua Brass 8x57mm JRS (8mm Rimmed Mauser) Box of 100. Lapua World-class brass begins with high-quality raw materials and superior smelting and metallurgical competence. Throughout the production process, the focus on quality control is consistent with Lapua’s exacting standards. Particular attention is paid to hardness, solidity and grain structure. All Lapua brass is tested to 30% overpressure according to Commission Internationale Permanente, the agency that oversees ammunition and component producers in Western Europe. This is not loaded ammunition.

Brass Preparation: With bulk rifle brass you may sometimes notice a few case mouths are “out of round” or slightly dented below the shoulder.  These imperfections occur in the final tumbling wash operation after the case mouth has been annealed.  Brass manufacturers are aware of the case cosmetics and have worked to mitigate it, but due to equipment design, denting may still occur.  Minor dents are normally removed in the first firing and will not affect case life or performance.  On non-plated brass, you may also notice all the anneal stain might not be polished off, which may give the case neck a pinkish color.  With some smaller caliber cases you may notice the case mouths to be slightly belled.

With all new rifle brass, you should first straighten out the case and case mouth, then chamfer and debur the case mouth inside and out.  To straighten the case mouth, run the case part way into the sizer die and let the expander ball straighten the brass.  To prevent the case neck from stretching, be sure to lubricate the case neck inside the case mouth.

What Mauser Ammo and Reloading Components do I need?

MidwayUSA carries JS and JRS 8x57mm (8mm Mauser) ammunition and brass. The standard 8x57mm JS Mauser is by far the most common version of this cartridge, used in military and sporting bolt action rifles. The less-common JRS Mauser is a rimmed cartridge developed for double barrel rifles. If you have a bolt action 8mm Mauser, you will want 8x57mm JS Mauser ammunition and components.