Works great and is properly machined - JP Enterprises Enhanced Firearm Extractor

Most extractors I've seen for 308 ARs (and 556 for that matter) don't have very distinct channels cut into the extractor claw. That means they don't get a really good grip on the case rim and that can cause them to slip off. The JP extractor is very nicely machined and has a deep, properly machined channel across the entire width. I've never had any extraction issues after switching to it.