Setting neck tension with expander mandrel and bushing die questions

[sedancowboy]

Not wanting to start a war but how does measuring seating force have any effect on bullet tension as it is released in a firing cycle. Just because you can buy measuring devices to measure seating force has no bearing on the amount of resistance the bullet will have upon release.
I will explain my thinking. As you increase the interference fit of bullet to neck beyond the yield point of the brass you are only using the bullet as a swage or mandrel instead of increasing the friction fit of the bullet to neck. You are also increasing the risk of deforming the bullet when seating force rises above the yield point of the brass. There is a reason most factory ammo crimps their bullets in place because delaying the bullet release increases ignition consistency.
I have fired ammo that had cold welded the bullet to the brass and noticed a increase in velocity. Break the cold weld by bumping the bullet with a seating die and there is a audible click as the bullet releases from the brass and the ammo will return to previous velocities.
I am not aware of a way for us to measure the force required for a bullet to be released from a loaded cartridge case in the firing sequence. Even if we could measure the amount of force required to pull the bullet from the case it is not relevant because the bullet is pushed from the rear by the powder gases.
Over the last 52 years that I have been reloading the most important thing I have learned is that consistency is most important to precision shooting. If you clean necks clean them all the same, if you turn necks turn them all the same. A .001-.002 interference fit is all that is needed anything beyond that you you are simply swaging brass when you seat the bullet.
My shooting precision improved most when I combined turning necks and annealing every time I reload a case. I found that every time a case is reloaded the neck tension changes if it is not annealed.

 

[Bobcape]

In the competition world of benchrest, F-Class and PRS a large percentage of the top 100 shooters use an arbor press with strain gauge to ensure consistent seating pressure. They have found that it DOES directly correlate to consistency of bullet release and greatly reduces ES and SD. ES is the killer for F-Class and PRS and all steps that can help control it are worth it for some competitors. Looking at my dope for my atmospherics, an ES of 30 fps is a difference of 25.35" at 1,000 yards. They are looking for chamberings, loads, loading techniques and equipment that makes single digit ES possible. So, for the right circumstances and the right shooter, an arbor press with a strain gauge for seating is a good choice.

Bob

ETA - Not attacking your post at all. Just adding a different perspective.

 

[30BR]

Yep, if you want to be sure, crimp.
For some guns, when I can push the bullet into the case by pressing a loaded round into the wood of my loading bench, I don't have enough neck tension. I pull it, size it with a smaller bushing, and then I can't push the bullet in by hand. Seating force, as I described, is a reflection of bullet tension; it doesn't effect bullet tension.

 

[antelopedundee]

Yep, if you want to be sure, crimp.
For some guns, when I can push the bullet into the case by pressing a loaded round into the wood of my loading bench, I don't have enough neck tension. I pull it, size it with a smaller bushing, and then I can't push the bullet in by hand. Seating force, as I described, is a reflection of bullet tension; it doesn't effect bullet tension.

That would be what's called a friction fit. I believe that some benchresters use or have used it.

 

[Old Rooster]

I am learning a lot guys and thank you very much.
I will get some graphite and since I reload shotgun shells I have #9 lead pellets to put in the graphite.
This might seems like your going over the same old stuff but folks like me that is working hard to reload better loads and get our ES down to single digits guys this is gold!
If a 338 Edge can hold a bullet and not allow set back with .001 neck tension I'm all in.
Graphite and a mandrel is on my list.A turning arbor will get you .002 neck tension and still force the irregularities outside and I am presently shooting with .003 neck tension,great groups but ES is double digit.
Turning Arbor or Mandrel?
Old Rooster

 

[cdherman]

I cannot speak to Arbor versus Mandrel. I use sinclair mandrels. I will share HOW I got to graphite and mandrels.

Several years ago, I starting tumbling my brass with stainless pins. This of course, produces the most wonderful looking brass. Squeaky clean. Perfect.

And it shot WORSE. That led me to some articles over at Snipershide, about the value of consistent neck tension. Several experienced shooters were surmising that the complete removal of all the powder residue from the inside surface of the necks was leading to greater variation in the neck tension. Several experienced shooters went to far as to suggest that their best accuracy was from brass that had been fired and just lightly cleaned and neck sized, leaving some powder residue in place. And several reported use of powdered graphite, both in freshly cleaned brass, but also in multiple firings.

So I started playing with graphite as lube and not cleaning my brass as often or radically. And my ES and accuracy got better.

Right about then, I also was playing with minimizing the amount of "work hardening" to the brass. I did not want to anneal every firing, because then I'd have to clean the brass up and start over again with no residue in the necks. That resulted in neck sizing with a bushing die. And then at the suggestion of another great thread, I tried the Sinclair mandrels. Again, the holy grail was consistent neck tension, with regards to both the brass hardening, the actual amount of resizing, and a consistent neck lube that did not need to be scrubbed out of the case.

I've been reasonably pleased. My ES are under 10 for a couple loads that shoot around 0.5 MOA. That's better than the guy behind the trigger can use....

 

[Bobcape]

@cdherman The two can be used together. Neck size using the appropriate Sinclair mandrel, prime and charge the case. Then seat the bullet on the arbor press with an in-line seater. It is definitely not necessary to take all of these extra steps, but it's the path some choose to follow in the name of single digit ES.

 

[Old Rooster]

Thanks for your journey to better groups.
I'll stick with mandrel's.If .001 neck tension keeps a 338 Edge bullet in place under recoil then I'm ok with mandrels.
Most of my rifles are 30 cal so 1 mandrel could be used for all 30 cal reloads right?
The others I could get a little at a time.
Take care all.
Old Rooster

 

[antelopedundee]

I've had a couple 6.5-06AI case shoulders collapse when trying to expand with a carbide mandrel [at least it's supposed to be carbide], but never had a shoulder collapse when seating a bullet.

 

[Old Rooster]

So antelopedundee do you presently use a mandrel?
If not what do you use?
You folks have made an old dog learn new tricks!
Thanks
Old Rooster

 

[cdherman]

I've had a couple 6.5-06AI case shoulders collapse when trying to expand with a carbide mandrel [at least it's supposed to be carbide], but never had a shoulder collapse when seating a bullet.

I'd think that if that happens, you may have sized the neck too small, or its in dire need of annealing. Or perhaps a touch of graphite is needed. I've not had that happen with my 280 AI. Maybe the 6.5-06AI, because it has a little "longer" shoulder, is a little more unstable though.....

The flat shoulder angle of an Ai cartridge could make it less stable I'd guess.

 

[antelopedundee]

So antelopedundee do you presently use a mandrel?
If not what do you use?
You folks have made an old dog learn new tricks!
Thanks
Old Rooster

Yes
I size with no expander and resize with a .255 or .262/.263 mandrel depending upon if I'm doing .25 or .26 cal. Even carbide mandrels seem to get brass stains. At times I may lube the inside of the neck with a bit of sizing wax.

 

[30BR]

...Most of my rifles are 30 cal so 1 mandrel could be used for all 30 cal reloads right?...

Not necessarily... Different brands of brass will behave differently and have different neck thicknesses. Different rifles may have different chamber diameters. Not off by much, but different. That's why I buy my own reamers and use the same gunsmith; so my 3 guns chambered in 6.5-284 can be as close as possible to each other. Brass with 3 reloads will behave differently from brass with 8 reloads, which is a good reason to anneal frequently. But generally speaking, yes, the mandrels will fit all 308 cases. But don't think the ONE mandrel will make all your .308 brass shoot the same.
(P.S. - Don't forget that I'm a benchrest type, and that colors everything I do. I try for the eyeball at 600 yds., figuratively speaking, on each shot. Heart/lung shots at 300 don't need the same kind of prep. Get your loads to where you're happy, and then PRACTICE. )

 

[Old Rooster]

Thanks for the reply 30BR I have seen that on some reloads.
Works great on 308 cases and even 30 06 and gives a tad over .001 neck tension but not quite .002 but 300 win mag is different as I can't get .001 neck tension.Different brass maker.
So I'm going to get a smaller mandrel for it and put it in the Redding box the dies are in.
The one mandrel I bought from 21st Century is black and coated with some of the slickest stuff I have ever seen.
You could use zero dry lube with this tool but I use a little anyway and run a brush through the neck of the brass to clean any graphite out.
Thanks for the help sir.
Old Rooster