What is your preference on neck diameter with a loaded round? 3 or 4 thousandths? This is for a no turn neck reamer. Thanks
Neck clearence on a Match Reamer
Below .003 will normally cause excessive pressure.
... All that's required is enough diameter for the case neck to expand in order to release the bullet. ...
Unless you pick a piece of brass that you think is going to be the largest ever encountered, I think setting the neck clearance at .002" for someone who isn't going to neck turn is a poor practice. I would never accept that from someone chambering a barrel of mine.
The term 'Match' in conjunction with reamer making has changed definitions over the years. I questioned Dave Kiff about his labeling some reamers as 'Match' and his response was, 'any reamers which had specifications outside of SAAMI/CIP spec were labeled 'Match" unless there was a specific name with known dimensions attached to a particular reamer.' The Diego XYZ Super Duper Atom Smasher.
None of the rifles I've built have used more than 0.004" for neck clearance including those used for Dangerous Game.
This is simply not true unless there are extenuating circumstances. Most of us have been using 0.002" clearance for the last 3 decades that I can think of and none of us have experienced 'excessive pressure' given normal circumstances. All that's required is enough diameter for the case neck to expand in order to release the bullet. On the other hand, everyone is entitled to an opinion about how they want to do their work.
Regards.
ADDED:
CIP, SAAMI and other specifications allow manufacturers to make cartridges and to cut rifle chambers that conform to rigid specifications. The specifications for chambers set a minimum size with an upwards tolerance. The specifications for cartridges set a maximum size with a downwards tolerance. This is to ensure that the smallest chamber for a given cartridge, will always accept the largest allowed cartridge. The manufacturers of reloading dies also follow these specifications.
When the smallest allowed cartridge is fired from the largest allowed chamber, accuracy will not be good. The critical dimensions for accuracy are the freebore and neck areas.
The maximum allowed difference will allow a clearance of 0.060 mm (2.4 mil)(0.0024") The closer to zero clearance one goes, the better the alignment will be and the easier accuracy will become.
When the cartridge is fired, any clearance between the cartridge neck and the wall of the chamber will become the clearance between the inside of the case neck and the bullet. The case expands away from the bullet until it contacts the chamber wall, before the bullet has moved much.
The more clearance there is between the case and the bullet, the more the long axis of the bullet can turn away from the centerline of the barrel. This causes the bullet to enter the rifling at different angles from shot to shot and results in different points of impact.
The term 'Match' in conjunction with reamer making has changed definitions over the years. I questioned Dave Kiff about his labeling some reamers as 'Match' and his response was, 'any reamers which had specifications outside of SAAMI/CIP spec were labeled 'Match" unless there was a specific name with known dimensions attached to a particular reamer.' The Diego XYZ Super Duper Atom Smasher.
None of the rifles I've built have used more than 0.004" for neck clearance including those used for Dangerous Game.
This is simply not true unless there are extenuating circumstances. Most of us have been using 0.002" clearance for the last 3 decades that I can think of and none of us have experienced 'excessive pressure' given normal circumstances. All that's required is enough diameter for the case neck to expand in order to release the bullet. On the other hand, everyone is entitled to an opinion about how they want to do their work.
Regards.
ADDED:
CIP, SAAMI and other specifications allow manufacturers to make cartridges and to cut rifle chambers that conform to rigid specifications. The specifications for chambers set a minimum size with an upwards tolerance. The specifications for cartridges set a maximum size with a downwards tolerance. This is to ensure that the smallest chamber for a given cartridge, will always accept the largest allowed cartridge. The manufacturers of reloading dies also follow these specifications.
When the smallest allowed cartridge is fired from the largest allowed chamber, accuracy will not be good. The critical dimensions for accuracy are the freebore and neck areas.
The maximum allowed difference will allow a clearance of 0.060 mm (2.4 mil)(0.0024") The closer to zero clearance one goes, the better the alignment will be and the easier accuracy will become.
When the cartridge is fired, any clearance between the cartridge neck and the wall of the chamber will become the clearance between the inside of the case neck and the bullet. The case expands away from the bullet until it contacts the chamber wall, before the bullet has moved much.
The more clearance there is between the case and the bullet, the more the long axis of the bullet can turn away from the centerline of the barrel. This causes the bullet to enter the rifling at different angles from shot to shot and results in different points of impact.
Not to start an argument. But this has been a misconception for many years and the only time less clearance than .003 should be used is if the neck is turned for a perfect chamber fit and loaded without any sizing. (This used to be common practice for bench rest shooters) all loads were less than maximum so pressure was not an issue.
No argument is intended. But stating that I suffer from a misconception is a falsehood plain and simple. Your experience or lack thereof possibly points to your background or misunderstanding of what is being stated. The shortest explanation revolves around experience and a desire to provide the best possible system for a client. My system has worked for a seriously long period of time and by sheer numbers, involving both extreme accuracy rifles and rifles meant for use on dangerous game. Neither has ever failed to provide for a client.
There has been and always will be disagreements regarding the technical and mechanical nature of firearms. We have seen the gamut of ideas change over the period of time for both aspects when efforts have been exerted to further our knowledge and understanding. It's bound to happen as we expand our realm of understanding.
So we disagree and there's nothing wrong with that. It always makes for a good discussion.
Regards.