Case Neck Separation. Why?

[243winxb]

Note the thicker brass near the neck shoulder junction. The expander hits & works the brass in this area. Lube doesnt help.
I have had the most neck separations with 223/5.56. After neck turning, the problem has gone away.
On the 243 Win, i use a Redding fl type S bushing die. Case life is a lot longer then standard dies.

 

[243winxb]

Cleaning brass - Dawn Ultra Dishwashing Liquid contains 5% ethanol.

Avoid cleaning with ammonia, vinegar and ethanol/alcohol products.
These chemicals can make brass brittle over time.

Annealing cant fix this damaged brass.

Google - dezincification & stress corrosion cracking.

 

[338 dude]

Cleaning brass - Dawn Ultra Dishwashing Liquid contains 5% ethanol.

Avoid cleaning with ammonia, vinegar and ethanol/alcohol products.
These chemicals can make brass brittle over time.

Annealing cant fix this damaged brass.

Google - dezincification & stress corrosion cracking.

Well now I know better!

 

[Mike D Texas]

Cleaning brass - Dawn Ultra Dishwashing Liquid contains 5% ethanol.

Avoid cleaning with ammonia, vinegar and ethanol/alcohol products.
These chemicals can make brass brittle over time.

Annealing cant fix this damaged brass.

Google - dezincification & stress corrosion cracking.

Interesting. What alternate cleaning solution is suggested?

 

[Alibiiv]

Took hardly any pressure to pull the neck off. Less than normal sizing operations.

I've always sized, then tumbled in order to get the primer pockets cleaned.

I'd like to recommend removing the primer with a universal decapping tool like RCBS or Lee ($20), I have a Lee decapping tool. I use a salt bath annealing system so decap to let the air out of the brass when I quench in water. Anneal the brass every second resizing on .270 Ackley Improved (fire formed necks/shoulders). There's definitely a difference in the amount of pressure needed to full-length resizing and neck sizing after the brass is annealed. After annealing I tumble the brass for about two hours in walnut media an a Hornady based polish. Then I resize my brass with a full-length resizing die with the expander plug removed and then size the necks with a Sinclair mandrel die for neck resistance/interference. Before resizing I use Hornady "One-shot" sizing lube and I do spray the necks before resizing. I have not had any issues with lube build up and wrinkled necks. I use a graphite lube on the case necks before using the mandrel for neck sizing. And the answer to your question, in my opinion, is a lack of annealing of your cases that have caused your necks to separate. A lack of cleaning could also have caused a build up of dirt inside of your full-length resizing die.

 

[epoletna]

Since you only had one case separate, it might have been a flawed case. But you might take a dental pick and slide it up and down inside the other necks to feel for hairline cracks inside.

My first thought was "work-hardened brass." But with only two reloadings, that seems unlikely. So what else could be the problem? Sizing the neck too small and then stretching it back out? Something that weakened the brass? Even this last point only resulted in the separation when you pulled the neck sizing button back through the neck, right?

All this points to reducing the neck too much and then pulling a button through it. Is your bushing reducing the diameter more than .002"? If so, try a larger bushing.

My experience is to measure the neck of a loaded cartridge, then get a bushing that reduces that .002"

 

[rsbhunter]

I just got into reloading for 6 Dasher, and using a new, well known die, sized the first case. Only sized about halfway down the neck because of the force required.....factory die made the neck look like I was changing caliber !!! Sent die off to mfg to hone I'd of neck to .002 under a seated bullet in case....Couldn't believe the amount of sizing being done...BUT, in defense of the die maker, they have to cover all chamber sizes,etc....definitely use bushing die or honed neck fl die ...just my .02...rsbhunter

 

[jimbires]

I can't buy the oversizing theory on brass this new , it's only the second fire . this brass isn't even fully expanded yet . I'll buy into a bad batch of brass way before over working . I can't speak for the OP on this thread , but for me , I'm using the same dies before this happened , and still using them . I usually get over 10 cycles on my brass in this rifle , it's usually the primer pockets get loose why I junk my brass .

 

[tnek13]

Thanks, I never knew that Dawn could cause dezincification. I have used it for over 20 years to pre-clean cases both black powder and smokeless as part of my reloading process, currently via an ultrasonic cleaner. Of course, the cases only sit in the solution a few minutes and are triple rinsed. The only failures have been well-used cases and a few 223 shells that were loaded and sat for 10+ years.

 

[DUSTY NOGGIN]

Took hardly any pressure to pull the neck off. Less than normal sizing operations.

I've always sized, then tumbled in order to get the primer pockets cleaned.

20$ rcbs univesal deprimine die ..

RCBS Heavy Duty Depriming Decapping Die

The RCBS Heavy Duty Decapping Die quickly removes primers from cases prior to cleaning and is ideal for a reloader with a heavy duty decapping or...

www.midwayusa.com

 

[DUSTY NOGGIN]

ive had facory brass be annealed bad from the get go .. extacted from the shoulder down only left the neck in chamber ..

its important to anneal down the body some (1/4" ish ) lower than the body shoulder junction

too thin of necks can be over annealed at the neck and not enough at the shoulder .. due to brass thickness differences .
annealing can be trickier with turned brass

 

[Deleted member 107796]

Did you lube inside the neck area before sizing? I only add that because I noted more die extraction force when I don't lube the neck.

 

[243winxb]

https://www.dudadiesel.com/search.php?query=citric&affiliate_pro_tracking_id=17:36:

citric acid- 3.5 tablespoons.
1 quart water
2 drops Dawn- Its diluted by the water. Just dont use a lot.



Use hot tap water. Mix in plastic container. I use old Tupperware. Shake & soak brass. Mostly i shake a few minutes, then let it sit 4 hours. Shake again then rinse.

OR- To clean 20 rifle brass, use fine steel wool on neck and shoulder, wipe clean. Brush inside of neck with RCBS nylon brush of the correct size.