Full Length or Neck Only; What's Best Resizing for Accuracy?

[Bart B]

I am a neck Sizer and that should enlighten you as to my opinion

I'm enlightened. But your reply is interesting.

Both sizing methods put the case shoulder well centered in the chamber shoulder when fired. And case body is clear of the chamber wall except when the case pressure ring is sometimes pressed against the chamber by the extractor. Some rifles push the case into and centered in the chamber shoulder before they are fired.

One resizing method ends up better centering the case neck on the case shoulder and therefore centering bullets better in the bore. That was proved in the late 1950's by one of the PPC cartridge developers who worked at Sierra Bullets.

 

[DJ Fergus]

I've done both, I do both ... I let my rifles determine what technique to use (not the internet). Having a great day shooting is what it's all about! Good thing the government isn't trying to tell us how to reload (yet)! LOL

I totally agree. I do both depending on rifle. The whole matter of what alot of people do when they full length sized perfectly is that they have basically used a full length die and 95% of what they have actually sized on the case was the neck & shoulder. That would be the ideal situation in full length sizing. But in my opinion many full length dies size the diameter of the case way farther down than needed. Now, you can still get those sized that way to shoot well. In a nutshell, if I can neck size only, that's what I do. But I'm not afraid to full length size either. The perfect situation would be to bump shoulder, neck size, & minimal size the diameter of the main case body.

 

[338 dude]

I'm enlightened. But your reply is interesting.

Both sizing methods put the case shoulder well centered in the chamber shoulder when fired. And case body is clear of the chamber wall except when the case pressure ring is sometimes pressed against the chamber by the extractor. Some rifles push the case into and centered in the chamber shoulder before they are fired.

One resizing method ends up better centering the case neck on the case shoulder and therefore centering bullets better in the bore. That was proved in the late 1950's by one of,the PPC cartridge developers who worked at Sierra Bullets.

Which method better ends up centering the case neck on the shoulder and therefore centering bullets better in the boar that was proved in the 1950s which one the OP asked which one What is better for accuracy!

 

[338 dude]

Crickets- now that's Enlightening

 

[DJ Fergus]

I don't think my idea of the perfect sizing die has been made but it it was it would: partial size the neck with a collet & mandrel, lightly bump the shoulder, & barely size the main case body diameter. This would be difficult to mass produce because of difference in chamber diameters. I would settle for a die that would just partial neck size with a collet & mandrel. A Lee collet die can be made to do that with a little work.

 

[Bart B]

Which method better ends up centering the case neck on the shoulder and therefore centering bullets better in the boar that was proved in the 1950s which one the OP asked which one What is better for accuracy!

Accuracy is best when bullets start into the chamber throat as repeatedly straight as possible.

 

[338 dude]

Accuracy is best when bullets start into the chamber throat as repeatedly straight as possible.

Good answer and that's not what I asked you said it was proven in the 50s I do not know the answer enlighten me which one

 

[DJ Fergus]

I just straight up neck size most of the time. I don't partial neck size but would like to start doing that when I have more time invest. But I don't see how you could ever get a more perfect case alignment in a chamber than a partial neck sized only case.

 

[Bart B]

The first thing to believe, know, understand and have confidence in, is the rimless bottleneck case does not rest in the chamber bottom when fired. It's a popular myth that's been around for decades. Sierra Bullets used to claim this and stated it in their early reloading manual.

A 2 ounce firing pin pushed by a 25+ pound force moving near 20 fps will drive a 1 ounce rimless bottleneck cartridge a couple thousandths inch forward until it stops against and centered in the chamber shoulder before the primer gets dented and fires the round.

Bolt face ejector's do the same thing when the round is chambered.

Therefore, case necks must be well centered on the case shoulder.

 

[338 dude]

The first thing to believe, know, understand and have confidence in, is the rimless bottleneck case does not rest in the chamber bottom when fired. It's a popular myth that's been around for decades. Sierra Bullets used to claim this and stated it in their early reloading manual.

A 2 ounce firing pin pushed by a 25+ pound force moving near 20 fps will drive a 1 ounce rimless bottleneck cartridge a couple thousandths inch forward until it stops against and centered in the chamber shoulder before the primer gets dented and fires the round.

Bolt face ejector's do the same thing when the round is chambered.

The OP just asked which one of the two methods was better for accuracy what I said was only my opinion you have your opinion as well but you stated this was proven in the 50s and you still haven't answered the question which sizing method works better Without all the numbers and mumbo-jumbo answer the question it is not right or wrong it is simply your opinion I have already stated mine

 

[J E Custom]

But wouldn't it work just the same if you were to do it after firing then after turning necks everything would realign on the next firing? The reason I am asking is I'm considering starting to turn necks. Want to be sure if I do that I don't have to start with new brass.

What I am trying to do is prevent the chamber from offsetting the inside of the neck buy the amount of the thickness difference. The chamber should be very concentric and when fired the case will take on the chamber shape and can move the case center.

If you turned the neck after the first firing the second firing would be necessary to realign the outside of the neck and a third shot would be the first loaded concentric case. This is what happens when you use once fired brass, and you need to prep it so in the end it will have been fired twice before it is concentric. New brass is once fired when concentrically loaded.

This is also the reason I anneal once fired brass before I Prep it. (It seems to fire form in an annealed state. So yes you can do it on the second firing, but you save one firing of the case before starting load development. Many times I have found loads that were very accurate during the second loading and was able to hunt with the remaining loads.

Concentric ammo always shoots better, so why not start with as good as you can get.

J E CUSTOM

 

[Bart B]

Full length sizing has been the norm for best accuracy for decades. It makes the most concentric cases. Dies whose necks are honed out to about .002 inch below loaded round neck diameter are popular, expander ball is removed so it won't bend the case neck.

I've typically got better accuracy with new cases compared to neck only resized ones; they're full length sized to start with.

 

[J E Custom]

The reason I full length size In the beginning, is to uniform case size for Case Prep.

Factory cases are not uniform enough to do a good volume test without sizing in your dies. dies are not exactly the same so if you use the die set you have, at least they will be very close.

Neck sizing new is not recommended because this will/can induce differences in the center of the neck as described in early post.

If a person is not going to do proper case prep then full size and shoot is the easiest way in my opinion.

J E CUSTOM

 

[DJ Fergus]

Hard to argue with folks who have won championship matches using full length sized cases.
One of my close friends won a FTR state championship with partial neck sized cases a few years back.
Hard to argue with that also.