number and twist of groves,barrel)

[gilles]

For a caliber such 6mm NORMA BR, manufacturors of barrels give a twist, ok for the bullets, for exemple 6,7,7.5,8,9,....16 but the number of groves 4,5,or 6 How choose and have the good choice? for me the problem is 107grs VLD bullets.

 

[Forum Boss]

There is a lot of anecdotal evidence that the three-grove barrels, when properly finished internally, clean-up faster than barrels with more lands/grooves. Broughton's 5-groove barrels have proved exceptionally accurate in the 6mm and 6.5mm calibers. The Rock and Schneider 5 grooves have also shown exceptional barrel life, but here, as with the Broughton 5C, we are talking about a profiled land that is tapered on one side. But nobody can really point to definitive test results yet. Krieger, whose opinion certainly must be given weight, has said, in response to the question "will fewer grooves shoot better?": "A: "There isn't any advantage to the shooter. Assuming the ratio of the surface area is kept the same, the number of grooves should not have any effect. Barrel makers use different numbers of grooves for ease of manufacturing and ... marketing hype."

More important, probably, than the number of grooves, is the consistency of the bore, proper stress-relieving, the absence of belling near the muzzle, and of course, a precisely cut chamber.