Call me frugal ... okay, I am cheap. While this doesn't count as a brass catcher, on my small-frame and large frame ARs I use a washcloth and 2 rubber bands. I have never had an issue with brass catching in the ejection port.It keeps brass close at hand and piles it nicely. If I need access to the right side for some reason, I can flip the washcloth up and over the scope.
Pretty simple:
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Rubber bands attach to either the levers or nuts of whichever mount I am attaching it to:
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Looks cheesy but works like a champ:
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