At this point I think at the least we are all in agreement that a tight neck chamber is NOT for hunting unless it is a controlled varmint type enviornment where the gun will not be susceptible to dirt and crap getting into the chamber. Some of the replys here still dispute the fact that a tight necked chamber will be more inherently more accurate than a standard SAMI spec chamber. Well, on that note you are wrong and there is no debating that subject as the bench rest community would not absorb the cost of special reamers if the was not a distinct advantage. Additionally, anyone that owns both will testify that their tight neck chamber guns regularly produce smaller groups.
As it relates to the insinuated statement that a standard SAMI spec chamber could possibly be on the tight side, wrong again. With the broad differential in neck wall thicknesses from the brass and ammunition manufactutrers the gun companies must insure that their chambering can accomodate the thickest of case necks by usually leaning to the large side of the SAMI spec. I once had an extended conversation with one of my old friends Neil Oldridge a retired senior vice president of Remington relative to this same issue and his explination was exactly as stated above.
Concerning neck turning brass for a standard SAMI spec chamber in an effort to standardize neck thickness in one lot of brass, another old friend, Jim Carmichael explained it this way: Traditionally there is a large differential between the chamber diameter and the neck case diameter in a factory gun. If you have brass that measures in a range of 13 to 16 and you turn the brass down to 12 1/2 you have increased the already large gap by 3 1/2 PER SIDE which is adding insult to injury. It would be far better to take off the high spots and use a bushing neck die with 3 different sized bushings to maintain consistent neck tension.
Sorry for beating a dead horse to death but I wanted to inject some expert opinions to help settlle a few of the points that seem to be continually argued in this thread. Can someone please tell me how the hell you attach photos to a thread like this? Thanks.
Last edited by Ackley Man; 03-24-2009 at 09:41 PM.
Tight necks produce smaller groups...period. BUT they are more finicky. However, it is not JUST the neck that produces a tighter group, but likely a combination of custom barrel with tighter tolerances throughout the barrel and the gun. I still say that if I cut an inch off my factory savage barrel, re-chambered it with a tight neck, accuracy would still not be what I would require, so clearly other factors are at work than just the neck. Not that I would do this but...
a standard SAMI spec chamber could possibly be on the tight side...
- Not sure I understand where you got this idea? SAMI is SAMI meaning "standardized" Factory rifles have to be standardized so Joe Smith can buy ammo from Winchester, remington etc safely.
Neck turning to take off a thou for a factory neck is fine with al least some improvement in accuracy likely d/t uniform neck tension on bullet release. Taking the brass to 0.012 is actually overworking the brass (work hardening) as it expands in a factory neck and even possibly prevents a proper gas seal around the neck. Not a good idea for a factory rifle.
Sorting by neck variance (cull cases w/ > 0.0015 variance) followed by neck turning to a uniform neck thickness is fast and easy (with the right tools) and will will most certainly outshoot ammo that has had no modifications because it is lined up with the rifling almost perfectly. A bullet with a thin side (common in win brass) means that bullet is than much off center with respect to the rifling. This runout can be negated by putting your bullet at or into the lands to some degree, but maybe not a good idea for a hunting rifle either.
click on the "insert image" button on the toolbar above where you reply to each thread. It has a small icon with a mountain on it?
Thank you for the info on how to do attachments. It is appreciated.
I love a good argument so let's carry on. "However, it is not JUST the neck that produces a tigher group, but likely a combination ....." Your statement is correct but I didn't say it was merely the tight neck not being in conjunction with anything else. Will you simply admit that a tight neck chamber will produce better accuracy? Remember the neck portion of the chamber is the last section of the chamber before the lead and throat. You also indicate that tight necks can be a "little finicky." Finicky in what sense? I have four in differenct calibers and have never had an issue related the the fact that they are tight necked chambers. Ya if you don't neck turn to the proper dimensions you can have issues (non accuracy types) but other than that I don't know of any associated problems with tight necked chambers.
"a standard SAMI spec chamber could possibly be on the tight side" NOT IN A FACTORY STANDARD GUN! To have one on the "tight side" you would have to have a minimum SAMI spec reamer used. Remington, Winchester, Savage, etc do not do this!!! I have two rifles that were reamed with minimum SAMI spec reamers. SAMI specs, if you have ever studied a SAMI chamber drawing have a min and max dimension. Your statement in paragraph two is contradictory. You indicate that it is possible to be on the tight side and yet you admit that that chamber necks must be cut to accomodate the variation in brass neck thicknesses.
I think that I may agree in part with your comments concening neck turning but I am not sure what side of the arguments your were taking. The point I was making was that previous replys to this thread stated that one should turn all of the neck to a standardized size. I disagree. If you are going to standardize a batch you have to cut to the thinest neck measurement in the batch. Obvioulsy, relative to a standard chamber neck even the thickest of factory brass would chamber. Accordingly turning the the thinest neck measurement will increase the differential between the brass and the chamber neck increasing the potential for alignment issues thus impacting accuracy. I disagree with your statement relative to overworking the brass. If multiple passes with the neck turner are made at a slow rate the will be little transfer of stress. Additionally, brass has much more ductility than steel and traditionally does not "work harden" without either severe stress being applied at one time or through repeated stimuli being exerted.
"Sorting by neck variance .............because it is lined up with the rifling almost perfectly." BACK UP THE TRUCK ON THIS! This would only be correct if the neck was tight. What do you think happens when the bolt face isn't square or the locking lugs are not true? Where will the bullet be pointing then? "The runout can be negated by putting your bullet into the lands." If your chambered round is out of alignment due to various factors I seriously don't believe you could jam the ogive portion of the bullet deep enough into the lands to correct the alignment and if you could I hope you never have to attempt to eject a loaded round because the bullet will remain stuck in the chamber and you will spill powder all over hell and back. Your turn.
Based on what I have read on this thread has brought up a question. What would be the minimum clearance on a tight neck chamber to allow it to be used in the field as a hunting rifle ? I know some previous posts have stated not to use a tight neck chamber for a hunting rifle, but would like some opinions on where to draw the line between the benefit of a tighter chamber for accuracy, versus to tight a chamber to where it would cause trouble in the field. Would .003 clearance on the brass to neck chamber be enough ? To rephrase the question, is there a happy medium between tight neck chamber for better accuracy and SAAMI spec dimensions ?