short necks.....what problem?

[MagnumManiac]

I have a question to those of you in the know.
I have been shooting a 300WinMag for over 20 years now, doesn't feel that long, and I have just been reading on another forum how neck length is critical to accuracy. I have never experienced an accuracy problem in my 300, even with it's imperfect neck length (according to some).

Now, my question is this, I have recently finished my 338Edge and it has a very short neck in regard to caliber, just as much as the 300, in my experience it has not taken much work to develop very accurate loads in both with known accurate bullets.

Why are these 2 cartridges so accurate if a long neck is the 'done' thing for accuracy, and where is their accuracy coming from if the necks are too short?

Any insight from you guys, it has me perplexed.

Cheers.
MM.
gun)

 

[MontanaRifleman]

Long necks are beneficial for 2 things that I can think of. One is reducing heat and abrasion on the throat and the other is to help keep bullets in line (concentric) when being jostled or worked through the mag and chamber, if you seat them deep in a long neck.

Not sure why anyone would say long necks are "critical" accuracy?

 

[Truc]

Not a hunting cartridge but the 6 Dasher has a very short neck and is one of the most accurate 600 yd cartridges out there

 

[MagnumManiac]

Not a hunting cartridge but the 6 Dasher has a very short neck and is one of the most accurate 600 yd cartridges out there

Yes, but why is it so?
If the belief is that a neck should be at least one caliber long for good accuracy, why do these cartridges go against the grain and shoot far more accurately than most that do have long necks that are generally longer than one caliber.

Cheers.
gun)

 

[Sully2]

I dont believe you can get proper ( enough) tension...i.e..grip on the slug

 

[MontanaRifleman]

Yes, but why is it so?
If the belief is that a neck should be at least one caliber long for good accuracy, why do these cartridges go against the grain and shoot far more accurately than most that do have long necks that are generally longer than one caliber.

Cheers.
gun)

I don't think it can be proven the a short necked cartridge can shoot any better OR worse than a long necked. Accuracy is more dependent on other factors. I ve seen a few long necked wildcats developed by some of our members shooting in 1's and 2's

 

[SAVAGE22-243AI]

gun)Working years ago for a ammunitions plant. Case capacity and neck tension were the two most important factors...............Powder capacity was needed more than grain to grain weight to get the worlds most accurate ammunition.
.308 shot 1/2" and less at 600 yds from machine rest.gun)5.56 tracer shot 1.6" and less at 600 yds with ball ammo shooting 1/2" and less. We could change neck tension and miss target.
I shoot a 22-243 AI and it has short neck and is the most accurate rifle I have................Ragged holes.gun)

 

[MagnumManiac]

I dont believe you can get proper ( enough) tension...i.e..grip on the slug

I've never had a problem with consistent neck tension in either catridge I'm talking about, which is why I'm asking this question.

There have been many old beliefs debunked of late regarding case design and other factors thought to be law to cartridge performance and function, but the major belief about neck length is obviously false, unless I'm missing some other factor that is causing my accuracy to be so good.

Cheers.
gun)

 

[Lefty7mmstw]

I've not seen an iota of difference in accuracy between long and short necked cartridges so far. I suspect a long necked round is actually capable of screwing things up more than a short necked round if neck tension isn't uniform.

 

[Trickymissfit]

thoughts:

* longer necks tend to help contain the T.P. inside the neck (but not always). You also must figure in the shoulder angle as well.

* longer necks do seem to help guide the bullet into the throat a little better. How much is debatable, but it does help.

* ideally a case design will have 1.5 calibers of neck, but most get by with a caliber or slightly more. In other words a 6mm will want a .243" neck length minimum, but the better ones are using lengths that are in the .30" to .35" area. Still a .25" neck length and a 20 degree shoulder will produce a short throat life as it places the TP in the throat. Yet the same neck with a 40 degree shoulder will place the TP right near the case lip. Somewhat better! But the same case with a .30" neck and a 30 degree shoulder is about ideal. Plus the 30 degree neck produces better gas flow than the forty degree neck.

* The one other serious issue with a short neck verses a longer neck is bullet placement inside the neck. Short necks often have the bullet seated well into the shoulder area when using very long high BC bullets. They also have another issue with very short bullets in that you can't seat them out as far, but that's usually an issue with factory chambers alone. Still if your chamber is cut for a high BC bullet that's long; you'll have issues with the short bullets. And of course vise versa.

* There are a couple other arguments in the short verses long neck concept, but I'm not digging that one up from the grave. I shoot both long and short necks, and know their demons.
gary

 

[Sully2]

I've never had a problem with consistent neck tension in either catridge I'm talking about, which is why I'm asking this question.

There have been many old beliefs debunked of late regarding case design and other factors thought to be law to cartridge performance and function, but the major belief about neck length is obviously false, unless I'm missing some other factor that is causing my accuracy to be so good.

Cheers.
gun)

I didnt mention neck tension being consistent...but if you have "X" tension for a neck .25 long...then compressed at the same rate the tension will be MORE in a neck say .30 or .35 long

 

[Mikecr]

IMO, load development removes the significance either way.
You seat bullets to best seating regardless of neck length.
You fine tune tension with length of neck sizing on any neck(long as it has a neck).

As far as the flamepoint provided by cal/shoulder/neck, this would apply to meaning more in some cartridges than others. I'm sure that defining real benefit/cost here would take a vast amount of testing, with a gamut of designs.
I've seen the flamepoint of a 6PPC at ~73.7% taken as a standard(but for no real basis).
To reach this: Neck Length = ((bullet dia/2)/(TAN(shoulder deg*PI()/180)))/0.737

 

[joe0121]

I shot my .300 win into the .3's not weight sorting brass or bullets shooting CCI BR2 primers that are supposedly not hot enough to light off 79 + grains of h1000. Shoot a quality rifle, Do your homework developing the load and you shouldn't have an issue getting MOA or better.

I do believe in longer necks helping with barrel life. You could of course Melonite your Barrels or use HBN and get plenty of barrel life for a hunting rig.

 

[MagnumManiac]

I didnt mention neck tension being consistent...but if you have "X" tension for a neck .25 long...then compressed at the same rate the tension will be MORE in a neck say .30 or .35 long

I agree with you, but as I stated, it appears that 'x' amount of neck length has little bearing on accuracy if neck tension is consistent. It has long been believed that the 300WinMag would have been far more accurate if it had had a longer neck when designed. I have used the 300-338 case with it's longer neck, not as accurate as my 300, either is my 300Weatherby.

I feel that the throat design has more bearing on accuracy than how long or short the neck is, I'm not the least bit concerned with barrel life, I've been doing this long range thing long enough to not really worry about throat erosion, I just keep altering charges to keep the velocity where I want it and don't bother chasing the lands, when accuracy falls off I put a new barrel on.

These are my thoughts, not based on any known theory, just what I have witnessed myself and what I think is occurring. If anyone would like to steer me straight, I'll bevall ears.

Cheers.
gun)