Charge Difference between Lapua and Hornady brass.

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I personally have not seen a video of the process of "smoothing the teeth" but it is something I've done for the last 5 or so uppers I've assembled. I do it before I put the barrel in the upper so I can see and feel what's going on and everything is wide open so to speak. The barrel extention lugs at 3 o'clock are the culprits of the cuts on brass. I've seen it on both 223 and 6.5 Grendel. The sharp edges coupled with a full length ejector spring work together (and with the likelihood of stout loads) in my experience to shorten the life of brass from this issue. I tend to use cratex tips and then polishing tips to smooth the teeth.

Sorry for the hijack....