Questions using expanding mandrel

[Dos XX]

 

[Bart B.]

A 0 to 50 pound hand scale connected to a collet type bullet puller and a shell holder clamped in a vise to hold the round is all you need. Accurate enough for us mortals to measure release force. A friend used his old trigger pull scale to measure his ammo. Setup mechanics should not be hard to figure out. I don't know if he called it a "tension gauge."

Yes, a thousandth inch interference fit from using a .002" under neck size is a good starting place. Use that scale like a chronograph if precise amount is needed for quality control. I don't care what velocity my bullets leave at. Plus or minus 75 fps guess error is close enough.

And does the military have those requirements for the sake of accuracy or is it because they dont want their bulk ammo all arriving with the bullets pressed back into the cases?

Both.

Accuracy for match and sniper ammo; 20 pound minimum, never measured any 30 caliber M72 or 7.62mm M118 and M852 over 30. Rebulleted ammo had about half that much.

60 pound minimum for service ammo to withstand rough handling, shipping and loading.

 

[dmoran]

I think "neck tension" with dimensional units is a poor descriptor for how tight case necks grip bullets. Here's why.

Turn 11 case necks also their thickness ranges from .007" to .017".
Size them so all their mouth diameter is .002" smaller than bullet diameter.
Which case neck wall thickness grips bullets the tightest?

Will soft brass case necks grip bullets with the same force as hard brass; all other things equal?

Do expander balls size case mouths to their exact diameter?

Military small arms ammo has a release (extraction) force spec for so many pounds is required to push or pull the bullet out of case necks. No such specification in SAAMI specs.

Machine shop term for pushing something into a space a tiny bit smaller than it is called an "interference (or press) fit." A couple thousandth inch interference fit will have a big range of extraction force needed to separate them; a lot for a bullet in a hole of hardened steel, very little for a hole in a marshmallow.

@Bart B.
When referring to neck tension, I am referring to the measured amount I size down the neck in relationship to its stretched measurement of the loaded round. The word "tension" means "state of being stretched", that in return for "neck tension" solely is referring to a measured amount of stretch of the case neck on the bullet.
Example:
0.267" = measured neck diameter after sizing, but before seating a bullet
0.269" = measured neck diameter after the bullet is seated
0.002" = the difference, and amount of measured neck tension in inches
Just my 2-Cents
Donovan

 

[X-Caveman]

@Bart B.
When referring to neck tension, I am referring to the measured amount I size down the neck in relationship to its stretched measurement of the loaded round. The word "tension" means "state of being stretched", that in return for "neck tension" solely is referring to a measured amount of stretch of the case neck on the bullet.
Example:
0.267" = measured neck diameter after sizing, but before seating a bullet
0.269" = measured neck diameter after the bullet is seated
0.002" = the difference, and amount of measured neck tension in inches
Just my 2-Cents
Donovan

Thank you. I also think that changing this to say .001" or .004" will make a measurable, repaeatable difference on target. Do you want to accomplish this with bushings early in your reloading procedure (and relying on impeccably turned necks) or with mandrels just prior to adding powder? The latter makes more sense to me.

 

[dmoran]

@AlloyTargets
I do both; size with a bushing, then my last case prep step is to expand with a mandrel before seating.
Donovan

 

[X-Caveman]

@AlloyTargets
I do both; size with a bushing, then my last case prep step is to expand with a mandrel before seating.
Donovan

Probably even better given the mandrels currently available on the market. But, what if you had mandrels in thou, or even 1/2 thou increments? Not you personally, just trying to explain why I think there's a market for them...

1. No need to keep brass segregated throughout your process- meaning the brass sized with different bushings
2. Perhaps we'd get better run-out because we can use a non-bushing die, which also allows for...
3. sizing all the way to the neck/ shoulder junction.
4. Running mandrels thru last allows you to round out the necks on the ones you dropped
5. You can also use them a go/no go guages to test/ segregate brass before seating.

 

[spclark]

@AlloyTargets
I do both; size with a bushing, then my last case prep step is to expand with a mandrel before seating.

Same here.

And I bushing neck-size only the portion actually in contact with the bullet's bearing surface once it's seated.

My fired cases chamber easily once sized in this manner; the un-resized neck portion ahead of the case shoulder still fits the chamber's neck ID, may very well contribute to aligning case to bore axis as well.

 

[Martin52]

As the case body is not held, is there a risk the mandrel does not align and create run out ? This was my experience some time ago , generating r/o of up to 0.004. Admittedly I did not use a rubber O ring to float the mandrel.

 

[spclark]

As the case body is not held, is there a risk the mandrel does not align and create run out?

I don't think it matters much if it does....

Case head is firmly against bolt face, case shoulder ought to be as well against the concentric angled shoulder profile between body & neck; case neck - if left partially unsized - is nicely centered in the neck bore. Any induced run-out should be negated by bullet aligning in throat once chambered, helped by case head being perpendicular to bore's axis with its being in firm contact at bolt face.

Why I also believe a minimum-clearance throat is a good idea, at least for single-loaded rounds for 600-1,000 yards.

What's the mantra? "Rat turd in a violin case" or some such....

 

[dmoran]

@Martin52
Myself, I float my mandrel die via o-rings. Concentrics stay unscathed for me !.!.!
Is something I do for all my press dies.
Donovan

 

[Martin52]

I am perservering with mandrels and will add an O ring. Always got good results with the Lee Collet die.

 

[Sheldon N]

I float my mandrel as well. Sinclair Gen II design is already a floating mandrel but I float it with an o-ring on the lock ring as well. No adverse effects, everything comes out at < 0.001 runout, even though I'm doing it on a Dillon press.

 

[Bart B.]

Do you guys think a 243 Win cartridge that's very straight will have its bullet perfectly centered in the throat of a 308 Win barrel if it's fired there?

The 243 case headspace is .002" less than the 308 chamber's headspace. 243 round's neck diameter is .276", 308 chamber neck is .344" diameter. 243 case body is .002" smaller than 308 chamber's body diameters.

 

[spclark]

Perfectly?

Nothing's ever perfect.

It'd make it down the bore, might even make it to a target down range.

(This a trick question??)

Don't count on that case being reloadable though, resized neck or not.

I inadvertently fired a 6HAGAR in a 6XC chamber a few years ago. Chambered up fine (headspace nearly the same) & went BANG when I pulled the trigger. The cloud of smoke enveloping my action & head though told me something was not quite right.

Case'd split along it's length yet as it was a 6mm the 105 actually hit the 6'x6' target out at 600 yards high & left. I kept the case as a reminder.

 

[Bart B.]

It's not a trick question. It's about bullet alignment to bore center.

I've no interest as to what happens to case and bullet after the primer fires.

Only asking how well centered the bullet will be relative to bore center when the round fires and there's lots of clearance from case neck to chamber neck.

People have all sorts of cartridge shape and dimension criteria they want their ammo to have.

I'm wanting to know how people think bottleneck cartridges head spacing on their shoulder position their bullet in the chamber when the primer fires.

Replace "perfectly" with "well centered" if you wish. Lots of people want perfect ammo. Change the cartridge to a 7-08 Rem, if you wish. Or chamber a 25-06 round in a 35 Whelen chamber and measure how well its neck centers in that 35 caliber chamber.

I've measured chambered cartridge case neck clearances to barrel chamber necks when in the firing position. Did I get an education that contradicts a lot of popular beliefs.

 

[fguffey]

I've no interest as to what happens to case and bullet after the primer fires.

I care what happens, I want the case neck to release the bullet, I want it to be able to expand enough to release the bullet. My case necks expand and release the bullet before the bullet moves, I know, there are those that wonder how is that possible. Of the neck can expand it can not be contacting the neck chamber meaning there has to be clearance. What does that mean? The neck can not align the case in the chamber if there is clearance and most of us should know a tight case neck in the chamber causes high pressure.

And then? There is the datum, as I have said for years and years there has got to be something reloaders do not understand about the datum. It seems in my effort to provoke reloaders and bench resters to think I only provoke them. There comes a time a reloader has to chamber the round and pull the trigger, there has to come a time when the reloader and bench rester has to give some credit to the design and builder of the rifle.

F. Guffey

 

[fguffey]

When it comes to clearance and centering the case I use feeler gages, I know, reloaders must have small base dies, I have small base die, I do not use them but I have them just in case. I understand the die is limited in its ability to reduce the diameter of the case head because of the deck height of the shell holder. My shell holders have a deck height of .125". According to C&H (El Monte, Cal) in the 60s they designed and made dies that were to be used with shell holders with a deck height of .125", for reloaders that read instruction know that because the C&H die box had the instructions printed on the bottom of the box. Today reloaders believe they have to match brands of dies with brands of shell holders because of the deck height. And I ask? "How fundamental is measuring the deck height of a shell holder?".

And then we go back to the shell holder and deck height, I can turn a standard die into a small base die with a feeler gage. I know that provokes, but I can also increase the presses ability to overcome the cases ability to resist sizing at the same time and I can use the feeler gage to size cases for short chambers at the same time.

F. Guffey

 

[Eddie Harren]

When it comes to clearance and centering the case I use feeler gages, I know, reloaders must have small base dies, I have small base die, I do not use them but I have them just in case. I understand the die is limited in its ability to reduce the diameter of the case head because of the deck height of the shell holder. My shell holders have a deck height of .125". According to C&H (El Monte, Cal) in the 60s they designed and made dies that were to be used with shell holders with a deck height of .125", for reloaders that read instruction know that because the C&H die box had the instructions printed on the bottom of the box. Today reloaders believe they have to match brands of dies with brands of shell holders because of the deck height. And I ask? "How fundamental is measuring the deck height of a shell holder?".

And then we go back to the shell holder and deck height, I can turn a standard die into a small base die with a feeler gage. I know that provokes, but I can also increase the presses ability to overcome the cases ability to resist sizing at the same time and I can use the feeler gage to size cases for short chambers at the same time.

F. Guffey

You are a man of many skills. Can you stand on your head, fart, and blow both socks off? I'm betting on Ya!

 

[gotcha]

oh, FFS. Get over it. If you *really* need it, I can give you a Google search that will provide thousands of examples of nomenclature that is not "technically correct", yet somehow, people still manage to communicate their meaning. Out of all your 1500+ posts, at least half are some variation of this stupid post. Just stop it already.

Anyone who would like to thank Jay PLEASE speak up. Thanks Jay

 

[ireload2]

English? Do you speak it?

When it comes to clearance and centering the case I use feeler gages, I know, reloaders must have small base dies, I have small base die, I do not use them but I have them just in case. I understand the die is limited in its ability to reduce the diameter of the case head because of the deck height of the shell holder. My shell holders have a deck height of .125". According to C&H (El Monte, Cal) in the 60s they designed and made dies that were to be used with shell holders with a deck height of .125", for reloaders that read instruction know that because the C&H die box had the instructions printed on the bottom of the box. Today reloaders believe they have to match brands of dies with brands of shell holders because of the deck height. And I ask? "How fundamental is measuring the deck height of a shell holder?".

And then we go back to the shell holder and deck height, I can turn a standard die into a small base die with a feeler gage. I know that provokes, but I can also increase the presses ability to overcome the cases ability to resist sizing at the same time and I can use the feeler gage to size cases for short chambers at the same time.

F. Guffey