Case Neck Concentricity

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   That sounds like a case for inside neck reaming, as opposed to outside neck turning?

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Shamu Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Logo Designer / Donating Member Joined: April 25 2007 Location: MD, USA. Status: Offline Points: 20510	Post Options Post Reply Quote Shamu Report Post Thanks(0) Quote Reply Posted: July 10 2023 at 4:34pm
	That sounds like a case for inside neck reaming, as opposed to outside neck turning?
	Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)

britrifles Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: February 03 2018 Location: Georgia, USA Status: Offline Points: 8404	Post Options Post Reply Quote britrifles Report Post Thanks(0) Quote Reply Posted: July 12 2023 at 5:06am
	If the chamber of the rifle has a relatively small neck diameter and brass is particularly thick in the neck, neck turning may be necessary. Some match chambers are indeed tight. The easiest way to check this is measure the neck OD on fired cases as add .001. Compare that to the neck OD of loaded rounds. There must be some clearance when the round is chambered, at least a few thousands, to ensure the chamber does not restrict release of the bullet. All my LE’s have about .007 to .010 neck clearance with a loaded round, which is a fair amount. Uneven neck thickness can affect neck tension, and consequently affect bullet velocity variation (standard deviation and extreme spread). It may also affect bullet runout to some degree. My 7.62 long range loads with Lapua brass was giving me single digit standard deviations in bullet velocity at the target, very good accuracy, so I see no need to turn necks. If chambers are on the large side, and you turn necks down, it will shorten the life of the case causing neck cracks to occur sooner.