using mandrel for neck tension

[Dirtlaw]

I've been thinking about this subject a lot though my experience does not compare with that of others who have commented. The ideal would be a case with a neck that was perfectly consistent in thickness. OR, getting one to be in that state when it originally isn't. If you seek perfection the hard part would seem to be getting the internal diameter perfectly round and then you can turn the outside just enough to have both internal and external diameters round and the thickness uniform as a consequence. Ideally thickness should be uniform round to round too for consistent tension , but overall the objective might be to keep as much "meat" as possible for the sake of economy. Sorry for the ramble, or rant, or whatever ... but this has been on my mind.

[smoothy8500]

I've been thinking about this subject a lot though my experience does not compare with that of others who have commented...Sorry for the ramble, or rant, or whatever.

I think you need a cup of coffee. Here's a neck turning tool to uniform the neck thickness:

[Dirtlaw]

I think you need a cup of coffee. Here's a neck turning tool to uniform the neck thickness:

Hey Smoothy, you should be a detective. I've been working since 1:30 this morning.

[ar15barrels]

Yes, I will be doing option 2. Mandrel to establish uniform necks, then re size and then with the bushing size the necks for .002 tension.

I just wanted to know if Im using the same brass, do I have to mandrel every time or just initially ?

In your system of non-consistent brass and therefore different internal diameters due to sizing, use them every time.

[smoothy8500]

Hey Smoothy, you should be a detective. I've been working since 1:30 this morning.

Nah, I'm not smart enough to figure out the crime. I got in line where we get paid to sleep, and brown chairs to watch TV.

[LynnJr]

DirtLaw
The benchrest crowd does indeed turn there necks and they use tight fitting chambers so the brass doesn't sit on one side of the chamber but us well centered.
The straighter a bullet starts down the bore the more accurate it will be all else equal.

Smoothy didn't show you the tip on his neck turner but if it's carbide version it has flutes that cut away the donut that forms at the neck/shoulder junction on all brass.
In the video linked above they show how seating a bullet past the neck/shoulder junction ruins your neck tension and thus your accuracy.

You will read countless stories about guys reloading for the 243 WSSM and getting bad accuracy. The bullets are seated way past the neck/shoulder junction so the loaded rounds will fit into the model 70 action and the donut destroys the accuracy.
Likewise the 338 Lapua came out at a time before we had 300 grain bullets so many guns in 338 Lapua will shoot much better with a 250 grain bullet than a 300 grain bullet unless you throat the chamber for the heavier bullets.
On all my 338 chambers I add 0.175 - 0.190 more Freeview which helps them shoot more accurately with the heavier bullets and gives you more velocity as well.
The "donut" you see at the neck/shoulder junction acts like a Venturi for our purposes here.

[fguffey]

Default using mandrel for neck tension

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Just had a quick question for using a mandrel for sizing inside neck for proper tension. Is this only done once like neck turning, or is it done after every firing prior to sizing?

Reloaders have an infatuation with neck tension,

Is this only done once like neck turning, or is it done after every firing prior to sizing?

Reloaders can not measure neck tension, if it was possible there would be a tool with an indicator marked off tensions, now they only have more or less.

My case necks are designed to hold the bullet, when I mention more or less I am talking about pounds. There is a tool that measures bullet hold in pounds, it does not measure interference fit, it does not measure crush fit.

I have a grinder that is used to make mandrels, the tool also grinds tappers and it is used to grind to length.

F. Guffey

[freonr22]

Reloaders have an infatuation with neck tension,



Reloaders can not measure neck tension, if it was possible there would be a tool with an indicator marked off tensions, now they only have more or less.

My case necks are designed to hold the bullet, when I mention more or less I am talking about pounds. There is a tool that measures bullet hold in pounds, it does not measure interference fit, it does not measure crush fit.

I have a grinder that is used to make mandrels, the tool also grinds tappers and it is used to grind to length.

F. Guffey

How many tensions do you seat at?

[JagerDog]

How many tensions do you seat at?

2.7 works for me.

[fguffey]

How many tensions do you seat at?

Again, I want all the bullet hold I can get, because I am the only reloaders that can measure bullet hold I am the fan of 'about' 45 pounds.

I was reading about the cautionary tale being distributed by reloaders I made a few small changes to my seating methods and tools. I managed to get 100 pounds of bullet hold; pulling the bullets was beyond the ability of the Hornady cam lock puller and the RCBS collet type puller.

SO? I dug out an old press, I made a change that allowed me to hammer on the handle while pulling the bullets. The bullets were destroyed before they were removed. The rounds with all of that bullet hold and still had the bullets were taking to the range. the 5 rounds with 'too much bullet hold' made one hole in the target meaning the bullets stacked. I know, the shooter has to have the ability and the rifle has to have the ability.

I built the rifle and one of my grandsons did the shooting..

F. Guffey

[J-cat]

45 pounds is not all the hold you can get. Factory ammo is higher than that.

[LynnJr]

F Guffey please watch the videos in the link and learn something.
The fact that you can't do something means nothing to those of us who can.
My scales measure in ounces grams pounds kilos and milligrams but none of them measures in scales
How can I use a scale if it doesn't measure in scales?
Why do they call it a scale if it doesn't measure scales.
Your argument is old tired and worn out and none of your guns shoot one hole groups period!

[fguffey]

45 pounds is not all the hold you can get. Factory ammo is higher than that.

I am the fan of bullet hold, I said I want all the bullet hold I can get; I said 45 pounds is about all the bullet hold I can get. And then I said I changed a few methods and tools and got up to 100 pounds+, POINT? 100 pounds of bullet hold was not too much bullet hold

Again, the factory can not tell a reloader how much neck tension the neck has on new ammo because the factory does not have a tension measuring machine. I do; problem, my tension gage measures in pounds.

F. Guffey

And now you are telling me the factory can measure bullet hold in pounds and you are telling me they can exceed 45 pounds of bullet hold?

And then there was the arsenal, they claimed they got up to 500 pounds+, the guys in the claims department claimed the necks did not come off with the bullet when fired.

[Jesse 2]

It depends on how you are processing your brass.
If you are neck turning to get the necks the same thickness and then using a bushing die or a sizing die with the neck honed to size your brass to a specific size, the mandrel would only be used before neck turning.
If you are not turning or using bushing dies or a honed die to eliminate excess sizing, you need to use the mandrel after each resizing to get rid of the excess neck sizing.

[J-cat]

I am the fan of bullet hold, I said I want all the bullet hold I can get; I said 45 pounds is about all the bullet hold I can get. And then I said I changed a few methods and tools and got up to 100 pounds+, POINT? 100 pounds of bullet hold was not too much bullet hold

Again, the factory can not tell a reloader how much neck tension the neck has on new ammo because the factory does not have a tension measuring machine. I do; problem, my tension gage measures in pounds.

F. Guffey

And now you are telling me the factory can measure bullet hold in pounds and you are telling me the can exceed 45 pounds of bullet hold?

And then there was the arsenal, they claimed they got up to 500 pounds+, the guys in the claims department claimed the necks did not come off with the bullet when fired.

Factory ammo is assembled with about 70-80 pounds. 45 lbs would result in bullet setback when feeding in an auto loader.