The .300 Olympic (aka .300 OSSM) is an answer to the questions about what MORE can one chamber an AR-15 to. Slightly exceeding the venerable .30-06 in horsepower with the lighter bullet weights, it uses the chubby .404 Jeffery case, necked down to accept 0.308" slugs and shortened enough to feed thru an AR-15 (2.160" LOA). A normal 20 round magazine for .223 becomes a single-stack and holds but 7 rounds. Uppers so chambered are available directly from Olympic Arms, as are reloading and case-forming dies, and factory-loaded loaded ammo (with 150 grain Speer Grand Slam bullets) is also available... I love mine so much that I sold my .30-06 bolt gun because I wouldn't be using it anymore... If I really need anything more powerful, I have my .45/100 Creedmoor, a Rossi M92 in .454, a custom .45/70 Siamese Mauser and my .458 WinMag Model 70...

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