I understand that chamber dimensions/throating can make big differences in both accuracy and velocity which is one reason reamer selection is important. Frank of Bartlein Barrels has mentioned this a few times in different threads but he didn't go on to discuss specific properties. Searches on the topic turn up very little conversation on the subject and even less objective information. So, I have basically two questions regarding just the throat portion of chambering:
1) All other variables held constant, what is your understanding of the relationship between throat diameter and accuracy? Do you find best accuracy from a throat that is exactly the same as the bullet diameter? .0001" over? .0002" over? .001" over?
2) Long free bore and long bullet jump (especially in factory barrels such as Weatherby) is typically associated with higher velocity and lower accuracy. The accuracy is most likely poorer because the throat of factory barrels is .002" or more larger than the bullet diameter and during this long unsupported travel, the bullet is allowed to yaw before and during its entry into the lands. It would seem that a very tight throat (of the same diameter as the bullet or .0001" over) would prevent this yaw and thus prevent any diminished accuracy from a long freebore while allowing for higher velocities than seating into or a few thousands off the lands. Can anyone weigh in on this?
1) All other variables held constant, what is your understanding of the relationship between throat diameter and accuracy? Do you find best accuracy from a throat that is exactly the same as the bullet diameter? .0001" over? .0002" over? .001" over?
2) Long free bore and long bullet jump (especially in factory barrels such as Weatherby) is typically associated with higher velocity and lower accuracy. The accuracy is most likely poorer because the throat of factory barrels is .002" or more larger than the bullet diameter and during this long unsupported travel, the bullet is allowed to yaw before and during its entry into the lands. It would seem that a very tight throat (of the same diameter as the bullet or .0001" over) would prevent this yaw and thus prevent any diminished accuracy from a long freebore while allowing for higher velocities than seating into or a few thousands off the lands. Can anyone weigh in on this?
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