To each his own I respect anyone's decision to do it anyway they want but yes I do not like people trying to influence my opinion if you oversimplify it anything that is a better fit should be more accurate in my opinion an AK 47 is known for running no matter what but they are also known for not being very accurate and all their tolerance are very loose that is my example
Full Length or Neck Only; What's Best Resizing for Accuracy?
- Thread starter Bart B
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Alex Wheeler
Well-Known Member
Centering a bullet in the bore? Thats not the job of the case. No matter how you size. Typically a freebore diameter is .0005" over nominal bullet diameter. In the real world you usually have .0001-.0002" of clearance around the bullet in the freebore in a well built rifle. Now if this is a sloppy rifle or a zero free bore then the case may have more effect on the bullet. As soon as pressure builds the necks start expanding and no matter how straight and aligned things were, you just dont have control over when happens as the neck opens. Keep in mind, full length sizing PROPERLY only reduces the case size a thousandth or two. Getting a die that works with your chamber is important. Well cut chambers usually work quite well with off the shelf full length dies like the redding s-die. Sloppy wallowed out chamber will need a custom die.
This is my thoughts also, in far to many situations the run of the mill and even alot of more expensive full length dies size the case way down farther than needed for most average chambers. If a fellow is going to have a custom FL die reamed to match his chamber for minimal case sizing, it would be hard to do another method that would be any better than that. Its difficult for me to say that a fellow could go buy a $39 or even possibly up to $200 mass produced die set and always, in every situation, & with any rifle have better results full length sizing than he would neck sizing in every single situation. There's a ton of variables there. If a fellow has the funds for a custom made FL die reamed for his chamber and if that cost is practical for his intended application, then that is what he should go with.
J E Custom
Well-Known Member
The reason I like to shoot concentric ammo in my chambers is exactly that. freebore is not there to center the bullet, it is there to allow the bullet to start moving at ignition and start engraving with some movement, Ultimately, you could have 3 or 4 thousandths as long as the case centers the bullet in the bore.
Many people seat the bullet against the lands to center the bullet and this is ok , but it increases the chamber pressure and negates the freebore function. The only reason the freebore is close to the bullet diameter is to aid in alignment of the bullet If it is not centered in the chamber or case before it engages the rifling. that is exactly what freebore does if the cartridge doesn't fit the chamber well from to much sizing.
In a perfect world, everything would line up with the barrel bore and all tolerances would be .0000
including freebore. and all brass cases would be the same in every aspect. but it is not a perfect world and hardly anything is perfect, so cartridge designers have to allow for these differences and except the negatives along with the positives. Any time you design a cartridge, you must except the effect of this difference and weigh it against the attributes of going with a conventional
design. so you end up with a compromise of pluses and minuses.
I believe that the better everything is aligned with the bore, the more consistent it will be and to me consistency means accuracy.
This is not only my opinion, it is my belief that everything needs to be as near perfect as possible and time spent to achieve it is not an issue. some find good accuracy with many different ways of doing things, but I find that time is not wasted in the quest for accuracy.
J E CUSTOM
Many people seat the bullet against the lands to center the bullet and this is ok , but it increases the chamber pressure and negates the freebore function. The only reason the freebore is close to the bullet diameter is to aid in alignment of the bullet If it is not centered in the chamber or case before it engages the rifling. that is exactly what freebore does if the cartridge doesn't fit the chamber well from to much sizing.
In a perfect world, everything would line up with the barrel bore and all tolerances would be .0000
including freebore. and all brass cases would be the same in every aspect. but it is not a perfect world and hardly anything is perfect, so cartridge designers have to allow for these differences and except the negatives along with the positives. Any time you design a cartridge, you must except the effect of this difference and weigh it against the attributes of going with a conventional
design. so you end up with a compromise of pluses and minuses.
I believe that the better everything is aligned with the bore, the more consistent it will be and to me consistency means accuracy.
This is not only my opinion, it is my belief that everything needs to be as near perfect as possible and time spent to achieve it is not an issue. some find good accuracy with many different ways of doing things, but I find that time is not wasted in the quest for accuracy.
J E CUSTOM
Muddyboots
Well-Known Member
Really nice thread but makes me wonder how any rifle is accurate with all that "slop" in the chamber! I look at accuracy as doing the same thing consistently every time to achieve a certain accuracy whatever that may be?
I look at accuracy as doing the same thing consistently every time to achieve a certain accuracy whatever that may be?When I first started shooting rifles, I couldn't believe that every bullet shot wouldn't go into the same hole. Now, Realizing all of the variables, I can't believe it was ever possible to get all of the fired rounds into the same hole. Lol.
bigngreen
Well-Known Member
The issue with being tight and looking for .0000 is it doesn't work over the long run, I experimented with this years ago thinking tight was the answer, only ran .0003 bullet clearance, turn necks with clearance that I barely sized anything, it would hold a bullet after firing even. It shot amazing but only some times, I had to sort bullet, sort brass then fire and mark cases and sort of any case that resulted in a flyer and it turned into a rabbit hole, pressures were exceptionally erratic, every time I fired a case the next time it changed a little. I took that exact same barrel and rebuilt the reamer to a good fit, .0008 bullet clearance, .004 on the neck and gave the body some room and actually sized cases. This made a whole new animal, gone was the being picky with spiky pressures, day to day was the same boring shooting without the manic OCD, when you build in some tolerances and quite forcing things it allows all the other components which have tolerances to play nice. I built rifles that absolutely hammered with one bullet, one lot and one brass now with a little bit of room you can tune the things to changes and your not screwed when a bullet comes in .0001 larger.
Rich Coyle
Well-Known Member
Perfectly?
Yes. Such cartridges have their bullet, case neck, case shoulder and case body axes perfectly aligned on one axis. Required when investigating fundamental case alignment issues to chamber and bore axes.
Alex Wheeler
Well-Known Member
If your planning to center a bullet better than the free bore does you better have less than .0002 tir on the concentricity gauge. If you think you can do that consistently, well then you may just be able to center the bullet with the case. The rest of us are using the free bore diameter whether we know it or not.
No commercial cartridge concentricity guage aligns bullets to the measuring device the same as the cartridge aligns its bullet to bore center when fired. Depending upon how each guage is set up, a given cartridge will produce different runout values across all gauges.
A perfectly straight cartridge is often crooked in the chamber when fired.
A perfectly straight cartridge is often crooked in the chamber when fired.
I will agree with you on all of those statements.
Also. The ejector holds pressure against the cartridge on one far edge of the case head. It seems to me that the more case to bore clearance there is that the more chances of the cartridge not sitting in the chamber exactly the same every time.
If anything pushes the rimless bottleneck case body's back end against the chamber wall the same for each round, that's not a problem. In spite of the bullet tip being tilted off center in the bore a fraction of how much the case body's back end is off chamber center but in the opposite direction. The cartridge pivots about its shoulder's contact point to the chamber shoulder.
