What causes this? (Neck "Lip")

[DocRDS]

I think I found a long running issue, but now to what caused it. Some of my brass doesn't chamber after sizing. It appears someone I've added a rolled edge that can be removed with a little extra case prep (de-burring), but I'm trying to understand why or how brass ended up this way. (Exaggerated cross section below--the red portion is about 0.001, just enough to prevent chambering in case guage, or chamber--some are worse than others )

Again, I can use my case prep tool to remove the red portion, but WHY is that appearing in the first place. Is that natural and I just need better case prep or an error in my sizing/reloading process

TYIA

 

[Mudflap621]

Is the brass bottoming out in a die? What dies and steps are you using?

 

[TheOfficeT-Rex]

We’re gonna need your process. Could be anything from bottoming out in a mandrel die to over zealous wet tumbling.

 

[cwinner]

I think I found a long running issue, but now to what caused it. Some of my brass doesn't chamber after sizing. It appears someone I've added a rolled edge that can be removed with a little extra case prep (de-burring), but I'm trying to understand why or how brass ended up this way. (Exaggerated cross section below--the red portion is about 0.001, just enough to prevent chambering in case guage, or chamber--some are worse than others )

View attachment 8245697

Again, I can use my case prep tool to remove the red portion, but WHY is that appearing in the first place. Is that natural and I just need better case prep or an error in my sizing/reloading process

TYIA

Wet tumbling with stainless steel pins is the most likely cause...... I've seen this numerous times. Cut down your wet tumbling time and chamfer/debur every time and you'll reduce your issues.

 

[morganlamprecht]

are you using bushing dies?

outside of the tumbling issues already mentioned, if youre using bushing dies and stepping down in too large a jump for your brass softness/hardness level to handle, it will make the mouth flare

 

[TEUFEL820]

Wet tumbling with stainless steel pins is the most likely cause...... I've seen this numerous times. Cut down your wet tumbling time and chamfer/debur every time and you'll reduce your issues.

I had the same issue. Wet tumbling with pins for prolonged time rolls the edges of the brass. Expanding the neck with a mandrel afterwards causes it to flare at the mouth. As cwinner mentioned, I now tumble for about 30 minutes and chamfer/debur prior to expanding the case mouth and problem solved. This is what worked for me. I would look at your process and eliminate the variables one at a time and you'll find the problem. Good luck!

 

[Dolomite]

Are you using the expander mandrel in the die?

 

[hollywood63]

Ok you have my interest I have noticed the same thing ...............and yes I wet tumble ............ I would typically set the timer for the full three hours and call it a day..............so I guess I'll back it down to 2 and see if it goes away as always very good info on this site

Thanks!!

 

[DocRDS]

Apologies for the delayed response.

Process:
Deprime: Lee Depriming Die
Wet Clean: FART, no pins 3 hours
Dry: Oven @ 200
Size: Hornady Die (no mandrel) Full Length, no bushing
Neck Mandrel: Wilson
Wet Clean: FART, no Pins 1 hour
Dry: Oven @ 200
Load

I just recently moved to the Neck Mandrel, before I used the deprime/mandrel with the Hornady die.

I've had a ton of problems sizing, I THINK this has been the problem for many of my "stiff" bolt close. I have the new precision shell holders so I don't have to mess with the tiny movements in the die and can just bottom out the press (Lee single stage)

Of note: I did the neck mandrel for 100+ virgin brass with 0 issues in firing.

 

[tomme boy]

Use a Lee FCD and it will not be there anymore.

 

[max1840]

I experienced the same issue and substituted a sonic cleaning to remove the sizing lube instead of tumbling with pins.

 

[918v]

It’s your cleaning, cases banging against each other and peening the case mouths.

 

[cwinner]

Apologies for the delayed response.

Process:
Deprime: Lee Depriming Die
Wet Clean: FART, no pins 3 hours
Dry: Oven @ 200
Size: Hornady Die (no mandrel) Full Length, no bushing
Neck Mandrel: Wilson
Wet Clean: FART, no Pins 1 hour
Dry: Oven @ 200
Load

I just recently moved to the Neck Mandrel, before I used the deprime/mandrel with the Hornady die.

I've had a ton of problems sizing, I THINK this has been the problem for many of my "stiff" bolt close. I have the new precision shell holders so I don't have to mess with the tiny movements in the die and can just bottom out the press (Lee single stage)

Of note: I did the neck mandrel for 100+ virgin brass with 0 issues in firing.

As your wet tumbling, this is the most likely cause, even without the pins the mouths will peen and cause the chambering issue issue your experiencing. Lots of folks confuse it with a sizing issue but it's not.

The simple solution is to insert a trim/debur step right before loading and you'll magically fix your problem and have bright shiny brass. I use a giruard trimmer and doing lots of 300 pieces is a snap......

 

[axarob44]

Use a Lee FCD and it will not be there anymore.

Not so on the newer Lee collet dies. They now cut the collet shorter and put an inside chamfer on the collet so that a portion of the neck (case mouth) remains unsized. This is supposed to make it easier to seat the bullet straighter. I think it sucks to be honest.

 

[CK1.0]

Wet tumbling.

WIth pins, versus no pins, matters not.

Stop beating the shit out of your cases every firing/loading cycle and it will stop (and likely your SD/ES numbers will improve also).

 

[918v]

Not so on the newer Lee collet dies. They now cut the collet shorter and put an inside chamfer on the collet so that a portion of the neck (case mouth) remains unsized. This is supposed to make it easier to seat the bullet straighter. I think it sucks to be honest.

He is referencing the Factory Crimp Die not the Collet Neck Die.

 

[AllenOne1]

Apologies for the delayed response.

Process:
Deprime: Lee Depriming Die
Wet Clean: FART, no pins 3 hours
Dry: Oven @ 200
Size: Hornady Die (no mandrel) Full Length, no bushing
Neck Mandrel: Wilson
Wet Clean: FART, no Pins 1 hour
Dry: Oven @ 200
Load

I just recently moved to the Neck Mandrel, before I used the deprime/mandrel with the Hornady die.

I've had a ton of problems sizing, I THINK this has been the problem for many of my "stiff" bolt close. I have the new precision shell holders so I don't have to mess with the tiny movements in the die and can just bottom out the press (Lee single stage)

Of note: I did the neck mandrel for 100+ virgin brass with 0 issues in firing.

Try this:
Everywhere you have "Wet Clean" & "Dry" in your process flow, cross those lines out and insert "Wipe clean with a shop towel". It's likely your issues will go away and you will cut hours off your prep time. Yes, it works just fine.

 

[whatsupdoc]

Apologies for the delayed response.

Process:
Deprime: Lee Depriming Die
Wet Clean: FART, no pins 3 hours
Dry: Oven @ 200
Size: Hornady Die (no mandrel) Full Length, no bushing
Neck Mandrel: Wilson
Wet Clean: FART, no Pins 1 hour
Dry: Oven @ 200
Load

I just recently moved to the Neck Mandrel, before I used the deprime/mandrel with the Hornady die.

I've had a ton of problems sizing, I THINK this has been the problem for many of my "stiff" bolt close. I have the new precision shell holders so I don't have to mess with the tiny movements in the die and can just bottom out the press (Lee single stage)

Of note: I did the neck mandrel for 100+ virgin brass with 0 issues in firing.

Pins and tumbling slightly peen the edge of the case but your diagram seems to show the case neck is slightly flared.

You are probably bottoming out the neck with the neck mandrel you are using to expand the case neck.

 

[375fan]

What cartridge? What is your case length measurement? Lets start there.

 

[DocRDS]

So minor follow up: how do you get case lube off without a wash/clean (even dry). Maybe I misread but I thought it was imperative to remove case lube.

 

[6.5SH]

So minor follow up: how do you get case lube off without a wash/clean (even dry). Maybe I misread but I thought it was imperative to remove case lube.

If only dealing with 100 or so cases at a time I rinse/wipe them off with denatured alcohol from a generic home depot spray bottle.

I have a plastic strainer I put over a plastic tub. The strainer has a flat area that ~20 cases can lay on. Spray them good and shake a few times and spray some more. With nitrile gloved hands grab a handful and roll them between my hands on a micro-fiber shop towel. Dump them in a cardboard flat so anything remaining inside or out can evaporate. I might go through 1.5-2 Oz of alcohol per hundred.

 

[CK1.0]

So minor follow up: how do you get case lube off without a wash/clean (even dry). Maybe I misread but I thought it was imperative to remove case lube.

Dry tumbler with 20-40 grit corn cob blast media (much finer than the usual corn cob most have seen), it pours out of flash holes like water when you're done (so you don't have to beat the crap out of your cases in one of those media separators).

Yes, removing every last bit of lube matters, I'm semi-nuts about it and let my cases go 8 hours overnight. I know that seems excessive, but since the gentle dry tumble doesn't beat the cases against each other like wet tumbling, no peening, no lip, just shiny brass.

 

[AllenOne1]

So minor follow up: how do you get case lube off without a wash/clean (even dry). Maybe I misread but I thought it was imperative to remove case lube.

Seriously, I just wipe it off with a clean white shop towel (Scots Paper Type) and move on to the next step. You may end up with a very thin layer of lube on your case but I've never seen any issues. I've dropped/ejected them on the ground after firing and nothing really sticks to them.

I was told to do this by a guy with many more years of reloading experience than myself, teaches reloading classes and is a current world record holder. So gave it a try and never went back. My cases don't look all shiny like the guys that tumble them though, so there's that.

Note: You should check closely that the mandrel isn't bottoming out on the case mouth and causing your issue as suggested by @whatsupdoc above.

 

[High Desert duck]

I’m with @whatsupdoc. I think it’s your mandrel. I’ve seen it before, you might not have seen it on the virgin brass because it was shorter, for instance lapis is normally .002-.004 short of trim length.

 

[OREGUN]

I’m with allenone1 on this. Wipe them off with a shop towel to remove lube (been working for me for years) or dry tumble in corncob (For like 30 mins). It’s less critical that they be COMPLETELY dry than you are probably thinking….wiped off with a reasonably clean cloth is plenty, cleaned with a solvent is overkill.

 

[918v]

I use a tshirt.

 

[918v]

I’m with @whatsupdoc. I think it’s your mandrel. I’ve seen it before, you might not have seen it on the virgin brass because it was shorter, for instance lapis is normally .002-.004 short of trim length.

Pls explain how it’s the mandrel

 

[High Desert duck]

Pls explain how it’s the mandrel

The case mouth is bottoming out against the mandrel where it steps from his desired diameter to the larger OD at the top. The brass is chamfered so the thinner edge is smashed down forming a ridge or a flare it’s not crushing the case because it is just kissing the bottom by a few thousandths

 

[Baron23]

The case mouth is bottoming out against the mandrel where it steps from his desired diameter to the larger OD at the top. The brass is chamfered so the thinner edge is smashed down forming a ridge or a flare it’s not crushing the case because it is just kissing the bottom by a few thousandths View attachment 8246403

Certainly one mode to cause this but there seem to be other potential causes and we don’t know that he’s bottoming out his mandrel.

I have the 21st Century due with a slot in the side so you can see amount of clearance and where your mandrel ends up on the down stroke.

Am I wrong?

 

[Oldloser]

I stopped messing with tumblers. Brass post fl resizing goes in the clothes washing machine with a full load of towels. Then sits under a hair dryer for ten minutes to ensure it's dry. I then check with a mandrel that does not bottom out and then trim in a little crow trimmer exactly set for my chamber.

Stuff coming out of the washer had few cases that had pressure in the mandrel - whilst the tumbled ones all had issues.

 

[Bacarrat]

The case mouth is bottoming out against the mandrel where it steps from his desired diameter to the larger OD at the top. The brass is chamfered so the thinner edge is smashed down forming a ridge or a flare it’s not crushing the case because it is just kissing the bottom by a few thousandths View attachment 8246403

I really can't see where wet tumbling would cause the necks to grow out a thou. But can see where if one was to bottom out on the mandrel it will. My 300WM will bottom out on the mandrel if I don't stop it in time. All my other calibers I can do a full stroke of the ram and it wouldn't bottom out. I also trim as the last step before loading....

 

[918v]

The case mouth is bottoming out against the mandrel where it steps from his desired diameter to the larger OD at the top. The brass is chamfered so the thinner edge is smashed down forming a ridge or a flare it’s not crushing the case because it is just kissing the bottom by a few thousandths View attachment 8246403

What you describe would collapse the shoulder.

 

[whatsupdoc]

What you describe would collapse the shoulder.

Yes it will, but first it will slightly flair the neck and then proceed to collapse the shoulder.
It depends on how far your attempt to make two forms of matter occupy the same space.

Now this may not be the OP's issue, simply a possibility.

 

[DocRDS]

I don't know yet what the cause is, but I'll apply the "guilty until proven innocent" experiment.

Will check after cleaning and of course after mandrel. Apprecaite the thoughts on what could be going wrong...and maybe have to break out my dry media tumbler.

Always learning something new.

 

[spife7980]

Certainly one mode to cause this but there seem to be other potential causes and we don’t know that he’s bottoming out his mandrel.

I have the 21st Century due with a slot in the side so you can see amount of clearance and where your mandrel ends up on the down stroke.

Am I wrong?

I just run a case up into the gutted die and check that way against the dies step, once its right below the lip without being above ill lower the case, install the mandrel and spin the top on.

 

[MJC]

are you using bushing dies?

outside of the tumbling issues already mentioned, if youre using bushing dies and stepping down in too large a jump for your brass softness/hardness level to handle, it will make the mouth flare

This. I don't wet tumble or use bushing dies and have experienced this same mouth flaring, as much as .003. Std fl sizing die without an expander. After using a mandrel to size the neck id the outward flare was gone.

 

[Northfl]

Are you using the expander mandrel in the die?

 

[morganlamprecht]

This. I don't wet tumble or use bushing dies and have experienced this same mouth flaring, as much as .003. Std fl sizing die without an expander. After using a mandrel to size the neck id the outward flare was gone.

Interesting…I didn’t think it would happen with standard FL dies, but I got almost zero experience with them. I started with bushing and stayed there since day 1. Learn something new everyday tho.

 

[iceng]

Post #9 said mandrel...

The case mouth is bottoming out against the mandrel where it steps from his desired diameter to the larger OD at the top. The brass is chamfered so the thinner edge is smashed down forming a ridge or a flare it’s not crushing the case because it is just kissing the bottom by a few thousandths View attachment 8246403

And i agree with @High Desert duck .. ive done this before. Mandrel was set too deep, and got a slight flare of the neck. Backed it out a full turn, was back to perfect..

 

[Haney]

Wilson Mandrel like this ? If so , I bet you are just kissing enough to flare it and not crush a thing as mentioned above .

 

[Baron23]

I just run a case up into the gutted die and check that way against the dies step, once its right below the lip without being above ill lower the case, install the mandrel and spin the top on.

hahaha....I'm sure that's how most people have done it for most of the past. I saw the die with the viewing slot and thought that was easy street.

A die made for idiots like me! haha

Cheers

 

[DocRDS]

hahaha....I'm sure that's how most people have done it for most of the past. I saw the die with the viewing slot and thought that was easy street.

A die made for idiots like me! haha

Cheers

That die got a name?

Uh asking for a "friend"

 

[Baron23]

That die got a name?

Uh asking for a "friend"

Expander Die Body

21stcenturyinnovation.com

Here you go....select what you want (e.g. I did not want their die rings...I have rings I like). Its the "window Gen X" die body

 

[B y r o n]

Since you did new brass and didn't have the issue yet you did later on with other cases, what was the length of the new brass and what was the length of the other brass? Sounds like the die was adjusted properly for the new brass and not for the other. Cleaning the brass has nothing to do with your problem.

 

[CK1.0]

Expander Die Body

21stcenturyinnovation.com

Here you go....select what you want (e.g. I did not want their die rings...I have rings I like). Its the "window Gen X" die body

@DocRDS, don't do it, I have one, and weirdly for a 21st Century product, it sucks. I mean it works, and does indeed have a window, but it's aluminum and feels cheap AF. If I ever were to drop it, it'd be 50/50 on whether or not I'd just throw it in the trash because that would more than likely compromise it in some way.

Stick with this one IMO:

SINCLAIR INTERNATIONAL GENERATION II EXPANDER DIES | Brownells

Our Generation II Expander Dies completely capture the mandrel within the die so the mandrel cannot pull out. An O-ring in the die cap allows the mandrel to float a bit and find its own center within the case neck. All three Generation II dies are...

www.brownells.com

 

[iceng]

KM Power Stroke 3 Hole Adapter with Mandrel Holder - Bench Rest Tactical

PowerStroke™ Version 2 (v2) Press Adapters (Patent Pending) are a significant advancement from our Version 1 (v1) by adding multiple radial holes to provide increased line-of-sight, full 360° visibility, and balanced stress distribution with a symmetrical matrix of port holes. Utilizing an...

www.brtshooterssupply.com.au

These. Theres others.... but this. Ill echo @CK1.0 i have WAAY too much 21stC gear. Its good. However their mandrel body is... sort of an after thought, not a design feature. Get a stainless KM. Worth it. 21stC mandrels in TiN are good, or any really that fit.

 

[CK1.0]

KM Power Stroke 3 Hole Adapter with Mandrel Holder - Bench Rest Tactical

PowerStroke™ Version 2 (v2) Press Adapters (Patent Pending) are a significant advancement from our Version 1 (v1) by adding multiple radial holes to provide increased line-of-sight, full 360° visibility, and balanced stress distribution with a symmetrical matrix of port holes. Utilizing an...

www.brtshooterssupply.com.au

View attachment 8247439
These. Theres others.... but this. Ill echo @CK1.0 i have WAAY too much 21stC gear. Its good. However their mandrel body is... sort of an after thought, not a design feature. Get a stainless KM. Worth it. 21stC mandrels in TiN are good, or any really that fit.

Dang, that is one badass-looking mandrel die.

 

[Baron23]

@DocRDS, don't do it, I have one, and weirdly for a 21st Century product, it sucks. I mean it works, and does indeed have a window, but it's aluminum and feels cheap AF. If I ever were to drop it, it'd be 50/50 on whether or not I'd just throw it in the trash because that would more than likely compromise it in some way.

Stick with this one IMO:

SINCLAIR INTERNATIONAL GENERATION II EXPANDER DIES | Brownells

Our Generation II Expander Dies completely capture the mandrel within the die so the mandrel cannot pull out. An O-ring in the die cap allows the mandrel to float a bit and find its own center within the case neck. All three Generation II dies are...

www.brownells.com

Well yeah...its aluminum....but he also makes steel ones (without the slot). I'm not really worried about the die body...its just a mandrel body and works well.

If I drop it and damage it then perhaps I'll look elsewhere but this die works, IMO.

Cheers

 

[CK1.0]

Well yeah...its aluminum....but he also makes steel ones (without the slot). I'm not really worried about the die body...its just a mandrel body and works well.

If I drop it and damage it then perhaps I'll look elsewhere but this die works, IMO.

Cheers

I wasn't coming at you or anything (I know that's hard to believe on the Hide lol).

I was more just commenting on how surprisingly flimsy it was coming from 21st Century... most of the stuff of theirs I've encountered (like their hand-prime tool for example) is built to last a couple of lifetimes, so their mandrel die body with the hole is kind of underwhelming (though, I bet I'd probably like the steel one).

 

[Baron23]

I wasn't coming at you or anything (I know that's hard to believe on the Hide lol).

Yeah, that’s the Hide, alright! Lol

I looked at the K&M product….and they seem to make really good stuff also…but thought it was a bit overkill for me.

Mandrel dies were a new thing I introduced to my process so I thought the slot was a very handy thing.

But I’ve since learned it’s pretty easy to do as @spife7980 described above.

But I still like the slot and the 21st die and mandrels seem to work just fine.

Have great day, friend