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

[J E Custom]

You have a habit of spelling out what others say in a lot more words

It would be much easier to just state something as fact without a detailed description of why or how and the newer shooters would still not know what you were talking about and be able to evaluate or understand whether on not it is the way they want to do it or be able to adapt to there way.

I think that details are good and easier to understand. Sorry you don't like my way of explaining things. But I am just a detail person.

J E CUSTOM

 

[Edd]

Not in the current SAAMI chamber shown on page 95 in their rifle cartridge and chamber document referenced in my earlier post #85. No freebore between chamber mouth and throat.

The 1 degree 22 minute angled throat (leade) starts at the .3106" diameter chamber mouth tapering to .3000" bore diameter.

My SAAMI print is a little fuzzy and I missed the 1 degree and only calculated the 22 minute angle. With a 1 degree 22 minute angle the freebore would be .044" instead of .1641".

 

[freefloater59]

without reading through all 115 responses, of which i'm sure there is excellent wisdom and experience, my $0.02 based on 50 yrs reloading... I FL size first then skim trim the neck. I do this for new or once-fires that are not from my rifles. If i'm reloading my fired brass, I back the die up 1/4 turn to get neck size only. I'll measure cartridge length and inspect for fatigue, etc. to be a bit careful. I have used rounds with this neck sizing method for decades without a single problem chambering. But I always use bolt actions and hunting accuracy has been completely acceptable...meat on the table.

 

[Bob Wright]

View attachment 168530
here is one example. Cartridge is .344 neck. Chamber is .346. Thus, then.002" difference
View attachment 168531
the 300wsm example, is the same.
Am I missing something ?

I read a lot of engineering drawings over the years. This one is to an old drawing standard.
Here's my best take:
The caveat is in the notes, "all calculations are at MMC"
MMC is "maximum material condition", where all exterior diameters are their largest per the drawing and inside diameters are their smallest.
So, .002 diametral clearance is the least clearance that must be met by ammo manufacturers and brass aftermarket manufacturers.
The drawing does not specify the minimum material conditions of the brass. So, they must meet a cartridge case that simply doesnt come apart on firing at the pressures identified for that chambering. Some brass is engineered better than others...
It's my best guess on this drawing style, but I doubt .002 clearance on the diameter is the norm, but it did cause pressure "excursions" on my rifle and neck turning was the fix (.004).
Reloading dies are just another variable.

 

[Mram10us]

It would be much easier to just state something as fact without a detailed description of why or how and the newer shooters would still not know what you were talking about and be able to evaluate or understand whether on not it is the way they want to do it or be able to adapt to there way.

I think that details are good and easier to understand. Sorry you don't like my way of explaining things. But I am just a detail person.

J E CUSTOM

I could be taking you wrong. I guess I assumed you were repeating statements and explaining the lengths you go to in building to set yourself apart and make yourself look better than others. If you are repeating posts to clarify for others, I apologize.

 

[Mram10us]

I read a lot of engineering drawings over the years. This one is to an old drawing standard.
Here's my best take:
The caveat is in the notes, "all calculations are at MMC"
MMC is "maximum material condition", where all exterior diameters are their largest per the drawing and inside diameters are their smallest.
So, .002 diametral clearance is the least clearance that must be met by ammo manufacturers and brass aftermarket manufacturers.
The drawing does not specify the minimum material conditions of the brass. So, they must meet a cartridge case that simply doesnt come apart on firing at the pressures identified for that chambering. Some brass is engineered better than others...
It's my best guess on this drawing style, but I doubt .002 clearance on the diameter is the norm, but it did cause pressure "excursions" on my rifle and neck turning was the fix (.004).
Reloading dies are just another variable.

What do you think the norm is if not the .002" the print shows. I'm ignorant to engineering prints but have a bit of experience with saami prints

 

[Bob Wright]

What do you think the norm is if not the .002" the print shows. I'm ignorant to engineering prints but have a bit of experience with saami prints

There is no normal. I would bet off the shelf guns are looser clearances and custom chambers (in my case) were closer to .003 or less ( cartridge brass dependant).
There are many kinds of brass and many chamber reamer manufacturers. No two are alike but close enough to meet the drwg.
I blew a couple of primers. I lead casted my chamber and found it. Neck turning fixed it. If I change brass, I have that number written down....out comes the neck turner.
Probably why 2 identical factory rifle won't shoot the same...tolerances from the bolt face to the muzzle.

 

[Mram10us]

I'd be surprised if saami had that .002" by coincidence without a good reason. I'll email them and post their response. It would be nice if it were described. Maybe it is and I missed it

 

[Bart B]

It's interesting to see which SAAMI standards some people follow while ignoring others.

 

[Tree Farmer]

When somebody provides information that you think is not entirely clear, it is appropriate to rephrase the information in a way that further clarifies the statement. If both statements are correct, it just reinforces a fact. I'd rather hear the same thing twice than be unsure once. Also, in my case, repetition helps me remember. I appreciate all the contributions.

 

[J E Custom]

I could be taking you wrong. I guess I assumed you were repeating statements and explaining the lengths you go to in building to set yourself apart and make yourself look better than others. If you are repeating posts to clarify for others, I apologize.

Again , You have it all wrong
I realize that I'm not always right and listen to others to learn More. I don't try to set my self apart from others because i am not better or more knowledgeable than many of the members and that would be a fools errand.

In any discussion, It is important to hear everyone's opinion or experiences to reach a decision which way to go. Just saying "That's a waist of time" or "Just do it my way" with out an explanation serves no purpose and it is no longer a discussion.

I read things all the time that I don't agree with for one reason or the other, But realize that it is there opinion based on there experiences and not mine. So i feel like I need to explain how I came to the conclusion I did and if they still believe they are right, so be it.

I don't have to prove anything to anyone and am very happy with my methods and If someone can Improve on these, I'm very interested and will listen to them.

Thanks for the apology but it's not necessary. You don't owe me one.

I am moving on now and I'm sure the membership is getting tired of this bantering back and forth, So if it makes you happy I will just not comment or post on any Of your post.

J E CUSTOM

 

[Bart B]

OK, time to toss some flies in the ointment.

I've got better accuracy with new cases compared to neck only sized ones. Both with custom match barrels and commercial rifle's barrels.

The new cases are full length sized ones.

Military teams shooting the very best semiautomatic M1 and M14NM service rifles rebuilt to the nth degree got best accuracy with new cases.

 

[RustyRick]

I'm convinced. Your first answer was the right one. "What ever you find works for you in your circumstances". I listened to a reloading seminar by one of TEAM USA Rifle competitor. He purported to FL. Then the debate started with World Class shooter who only NS. That was at the Berger Southwest Nationals.

I think one thing that determines what you do is how close your die and chamber match.

 

[Bart B]

I'm convinced the best accuracy happens when resized case necks are best straight and centered on the case shoulder. That determines how well centered bullets are to the bore axis when fired in cases headspacing on their shoulder.