Overexpansion of neck on a Mauser 7x57

[Pops70]

G'day all,

I'm new here and could do with some help.

Long story short, I am trying to reload some Federal 7x57 ammo for my Mauser K98, which was re-barreled to that calibre.

The cases do NOT go into my Lee 7x57 FL resizing die after being fired with out excessive force and if I resize bit by bit, some come out but I have had three of five stuck with the rim sheering off when trying to extract the case.

If I cut the neck off one fired case, I can resize it comfortably

To me it seems as if the neck gets stuck if it is forced into the die and then the rim sheers off when trying to extract. I know that I should never have to use that much force, but I am just trying to figure out what the hell is wrong.
The neck size is defiantly way over size after firing (see measurements below .... 8.35 mm compared to 7.84 coming out of the die)

We tried another new die with my fired cases in the gun shop with the same issues.

Also tried brand new 7x57 cases which did NOT get stuck (manufacturer evades me currently).

Measurements:

Federal 7x57 Factory ammo BEFORE firing:

Neck diameter 0.314
Shoulder diameter 0.422
Base diameter 0.466

Federal 7x57 Factory ammo AFTER firing:

Neck diameter 0.328
Shoulder diameter 0.438
Base diameter 0.471

Hornady Handbook of reloading 10th edition:

Neck diameter 0.321
Shoulder diameter 0.429
Base diameter 0.471

Can someone look up the neck diameter for me in their Lee reloading Handbook?
What neck size does a Hornady FL die produce?
I'd somehow love to slowly get from the expanded neck to a usable neck without getting the case stuck.

Any help would be appreciated.

Cheers

Tim

 

[std7mag]

I'm trusting you ate lubing before resizing?
I use a Qtip and lube inside, outside of neck, and the body.
Don't lube the shoulder.

 

[Pops70]

I'm trusting you ate lubing before resizing?
I use a Qtip and lube inside, outside of neck, and the body.
Don't lube the shoulder.

Yes mate.

I reload quite a few 303 and know what tight can feel like and this is excessive force required.
Even lots of lube changes nothing at all.
See picture for sheered off rim when trying to extract.

 

[Pops70]

You can even SEE the difference.
Left factory and resized, right fired.

 

[358WCF]

What do the cases you have sized successfully measure?

From my rifle new PPU brass measures .313, .429, .469. Resized twice fired PPU in an RCBS FL die measures .312, .430, .470.

Fired WW brass measures .322 at case mouth, .325 at base of neck, .432 at point of shoulder, & .473 at pressure ring.

Your chamber is larger up top than mine, but not all that much. It sounds like lack of lube or a defective sizing die from your information so far.

 

[DGP4]

I suspect your rifle was never rebarreled in 7MM and you are firing 7MM ammo in an 8MM rifle. You need to make a casting of your chamber to be sure!

 

[Pops70]

I suspect your rifle was never rebarreled in 7MM and you are firing 7MM ammo in an 8MM rifle. You need to make a casting of your chamber to be sure!

That is one thing we will be doing. I've already ordered some cerrosafe.

Barrel states 7x57 with British proof markings.

Measures 7mm at the dangerous end with electronic calipers

 

[Pops70]

What do the cases you have sized successfully measure?

From my rifle new PPU brass measures .313, .429, .469. Resized twice fired PPU in an RCBS FL die measures .312, .430, .470.

Fired WW brass measures .322 at case mouth, .325 at base of neck, .432 at point of shoulder, & .473 at pressure ring.

Your chamber is larger up top than mine, but not all that much. It sounds like lack of lube or a defective sizing die from your information so far.

I'll measure one when I'm home.

We just ordered a Redding neck sizing die which is not a FL die and sizes the neck differently. See how we go with that one.

 

[Homerange]

Pops70, is it possible you have the neck sizing button set too high in the die so the neck engages with it before the case neck leaves the outer part of the die ?

 

[Pops70]

Pops70, is it possible you have the neck sizing button set too high in the die so the neck engages with it before the case neck leaves the outer part of the die

 

[Pops70]

It’s a Lee FL die. I don't think so. Even if I remove the rod which pushes the primer out and then forms the neck on the inside on its way out, the neck does not go into the die without tremendous force.
No other adjustment available.

 

[mac86951]

Hmm, that does sound excessive; wonder if a 7.5x55 reamer was used instead... +2 for cerrosafe the chamber and measure what's going on.

-Mac

 

[hoz53]

G'day all,


I'm new here and could do with some help.


Long story short, I am trying to reload some Federal 7x57 ammo for my Mauser K98, which was re-barreled to that calibre.


The cases do NOT go into my Lee 7x57 FL resizing die after being fired with out excessive force and if I resize bit by bit, some come out but I have had three of five stuck with the rim sheering off when trying to extract the case.


If I cut the neck off one fired case, I can resize it comfortably


To me it seems as if the neck gets stuck if it is forced into the die and then the rim sheers off when trying to extract. I know that I should never have to use that much force, but I am just trying to figure out what the hell is wrong.
The neck size is defiantly way over size after firing (see measurements below .... 8.35 mm compared to 7.84 coming out of the die)


We tried another new die with my fired cases in the gun shop with the same issues.

Also tried brand new 7x57 cases which did NOT get stuck (manufacturer evades me currently).



Measurements:



Federal 7x57 Factory ammo BEFORE firing:

Neck diameter 0.314
Shoulder diameter 0.422
Base diameter 0.466



Federal 7x57 Factory ammo AFTER firing:

Neck diameter 0.328
Shoulder diameter 0.438
Base diameter 0.471



Hornady Handbook of reloading 10th edition:

Neck diameter 0.321
Shoulder diameter 0.429
Base diameter 0.471



Can someone look up the neck diameter for me in their Lee reloading Handbook?
What neck size does a Hornady FL die produce?
I'd somehow love to slowly get from the expanded neck to a usable neck without getting the case stuck.


Any help would be appreciated.


Cheers


Tim

so you have removed the decapping rod and tried to size one without it and it still sizes very hard? either die is to small or chamber is to big. you say though you tried another sizing die right? that points toward the chamber. i can size an 06 case down in my 7x57 rcbs sizing die to 7x57 without much effort. it could just be the lube your using. ill measure some of my 7x57 fired brass tomorrow. if you havent used imperial lube try that.

 

[Pops70]

so you have removed the decapping rod and tried to size one without it and it still sizes very hard? either die is to small or chamber is to big. you say though you tried another sizing die right? that points toward the chamber. i can size an 06 case down in my 7x57 rcbs sizing die to 7x57 without much effort. it could just be the lube your using. ill measure some of my 7x57 fired brass tomorrow. if you havent used imperial lube try that.

I believe it's not the lube as I have had nil issues with any of my 303.
Yes, de-capping rod out.

Yes, I tried another die at the gunshop and it was the same.

Once I have the cerrosafe, I will be able to get an accurate measurement of the chamber.

 

[Pops70]

What do the cases you have sized successfully measure?

From my rifle new PPU brass measures .313, .429, .469. Resized twice fired PPU in an RCBS FL die measures .312, .430, .470.

Fired WW brass measures .322 at case mouth, .325 at base of neck, .432 at point of shoulder, & .473 at pressure ring.

Your chamber is larger up top than mine, but not all that much. It sounds like lack of lube or a defective sizing die from your information so far.

Sizing them "successfully" still ends up with unusable cases because the rim has been stressed trying to get the case out. So not an option using this die for my Mauser Brass.

This unusable resized brass measures at: .308 at case mouth, .432 at point of shoulder and .466 at pressure ring

 

[Homerange]

Sizing them "successfully" still ends up with unusable cases because the rim has been stressed trying to get the case out. So not an option using this die for my Mauser Brass.

This unusable resized brass measures at: .308 at case mouth, .432 at point of shoulder and .466 at pressure ring

It should measure .284. Does the expander plug measure ~0.284" ?

 

[Pops70]

It should measure .284. Does the expander plug measure ~0.284" ?

It's .282 ... so close but I have tried without the plug and it's all too tight.
I think the die is ok .... it's the chamber in the barrel letting the neck get that big, you can fit an elephant through it ... ;-)

 

[Homerange]

It's .282 ... so close but I have tried without the plug and it's all too tight.
I think the die is ok .... it's the chamber in the barrel letting the neck get that big, you can fit an elephant through it ... ;-)

So what exactly are you using for a case lube ?

 

[Pops70]

So what exactly are you using for a case lube ?

Tried both Lee Resizing Lubricant and Hornady one shot case lube.

 

[Pops70]

So what exactly are you using for a case lube ?

You are actually kidding me .... I just thought about it again and not just put a little bit of the Lee Resizing Lube on the case .. but lots ... and guess what ....
EVERYONE was right .... the lube IS the issue.