Remember that opinions are worth exactly what you pay for them. Having said that, here’s mine. I believe you guys shoot mostly at 600. There is nothing more competitve than a 6BR Norma when the wind is consistent or low. If the wind is changing from 4 -7 miles an hour (and it ususally is), you will have more trouble bracketing or holding the 6BR in the 10 or X ring. The gentleman that said you only gain about 150 FPS is exactly right however that particular gain which is gonna be somewhere between 2850 and 3000 roughly, is critical for maximum BC if you are shooting an 8 TWIST, 105 gr Berger VLD, (which you should be in any case). Now all this tech aside, on a wind switching day, the 6BR Norma is gonna drive you crazy. On a calm day, everyone else can go home. LOL. I would recommend the Dasher or the 6mmX47 Lapua which is formed from 6.5X47 brass with a single stroke into a FL resizing die. The 6BR Norma is actually my favorite cartridge, but I don’t shoot them in 600 F-Class matches anymore. Remember 8 twist, 105 Berger VLD. In the Dasher or the 47 it’ll do wonders even out to 1000.