One of the best brass catchers on the market - Caldwell AR-15 Picatinny Rail Brass Catcher

If you are moving around plinking targets, and trying to save brass - this is the answer. I have used the velcro strap on models that several companies make, but this one really works. The design keeps the net open all the time. Yes, you might get an occasional brass hung up, but I have shot several hundred rounds shooting prairie dogs using this brass catcher and it worked like a champ, with no glitches. The mounting bracket can be located in the front, middle, back, or anywhere in between - making it fit most conditions. I have a high power scope with Larue mount - I have mine mounted around the forward assist, and had to shift my scope and mount forward one notch so it would sit right over the ejection port - not a big deal. Highly recommend.