Case collapse while using mandrel

[Webster]

The brass is TOO SOFT!! Back off on the annealing. Been there, had the same thing happen to me. Annealing is good but too much is bad. (as you found out) We learn as we go.

And NO, you DON'T need 20 people to tell you how to get oil on a neck or mandrel. A little dab will do ya.

I doubt the AMP over annealed the case. I assume he ran the analyze program ciorrectly. I don't think he mentioned if he needed excess force on the lever to get the mandrel in.

He said the cases sized OK after cleaning the dirty mandrel. No replies seemed to pick up on this. What I would do is after annealing , clean the neck o.d. with a little 0000 steel wool, spin a nylon brush inside the neck and lube the mandrel. This is going a lttle beyond when he said the cases sized OK after cleaning the mandrel. This suff isn't complicated folks. I never damaged a case shoving my lubricated neck turner mandrel into a neck in over 30 years. Never noticed the mandrel getting dirty.

 

[NZ_Fclass]

40 deg shoulder cases are much more prone to collapse than others. I have only a couple calibres with 40 deg these days - and both are hunting rounds.
For lubing the mandrel I simply wipe a little Imperial wax across the case mouth on every 5th or 6th case and wipe it out with a cotton bud - to prevent powder sticking later. I did acquire a dry lube set up a while ago, but so far, I haven't used it.

 

[Homerange]

40 deg shoulder cases are much more prone to collapse than others. I have only a couple calibres with 40 deg these days - and both are hunting rounds.
For lubing the mandrel I simply wipe a little Imperial wax across the case mouth on every 5th or 6th case and wipe it out with a cotton bud - to prevent powder sticking later. I did acquire a dry lube set up a while ago, but so far, I haven't used it.

Remind me to show you my dry lube setup next time you visit.

 

[Fire Dog]

What is your Neck I.D. before NECK SIZING?
After neck sizing but without mandrel?
You didn't mention body sizing.

I have never bothered to check but the chamber is “No Turn” and a fired case will allow a projectile to slide inside, just… In this case a 7mm/.284” so I would assume that before sizing the ID would be just slightly larger by perhaps one thousandth giving half a thousandth all around the .284” of the bullet.
I use a full length Redding sizing die without the de-capper/expander setup {Have a Harvey de-primer} then expand the neck with a 21st Century expander die body and one of their black nitride neck turning mandrels as that is just the right amount of neck tension. About .0015”
I assume that the sizing die reduces the ID at least 2-3 thousand of course the neck wall thickness of any given brass will effect that a bit but the Peterson brass that I am using sizes smoothly and now that I am using a bit of lube on the inside of the neck the issue of collapsing the case when expanding has stopped.
I have also had a case neck pull off the case {case was old, fired many times in a semi-auto and un-annealed} when using a die with an expander ball indicating that there is certainly a lot of force/friction at play when the neck is being expanded whether by mandrel or by using the expander ball being pulled through the neck of the case.
When expanding the case neck with the standard die and expander ball setup there is every chance of stretching the case shoulder back forward after the case is sized if the friction is significant.
Using a spinning bore brush inside the neck after the clean and annealing, chamfering the inside and outside of the neck to eliminate any peening from the wet tumbling has the case back to as close to “Factory New” as I can make it before resizing and expanding the the neck.

 

[Fire Dog]

You tumble in rice just to get rid of the lube? Does it clean the brass also? I find that my cases are nice and shiny after wet tumbling, but with lube and handling through all the rest of the steps, it dulls out a lot.

Wearing nitrile gloves will reduce the the amount of sweat contact to your cases and keep associated contaminants off you hands.
If you add about 10ml of BoreTec sonic cleaner to you tumbler drum it seems to add a bit of tarnish resistance to the brass. Also do a 24 hour pre-soak with your Lemishine and dish-soap and 10ml of the BoreTec sonic cleaner with hot water will help reduce tumbling time and associated peening of the case mouth.
If you can get some “Burnishing Compound” you will be amazed by the results!
I source mine from a lapidary supply house. Two tablespoons in the drum with all the above products and HOT water should see your brass sparkling with only 1 & 1/2 hour of tumbling.
The loaded rounds will look like a box of polished factory ammo….{:~)

 

[Fire Dog]

40 deg shoulder cases are much more prone to collapse than others. I have only a couple calibres with 40 deg these days - and both are hunting rounds.
For lubing the mandrel I simply wipe a little Imperial wax across the case mouth on every 5th or 6th case and wipe it out with a cotton bud - to prevent powder sticking later. I did acquire a dry lube set up a while ago, but so far, I haven't used it.

I’ve used dry lube in the past {Bonanza/Foster setup} but found having to run the case up and down the brushes and having to put the lid back on and shake the powder back onto the brushes about every 10-15 cases to be a nuisance. The “dip it into a tub” of black or white powder with small ceramic balls also means that you wind up with powder on the outside of the case as well making a mess in handling, especially the black Moly stuff!!!
None of the dry lubes have given me as good results as the homemade Neolube2 and since no one sells it in OZ and it apparently cannot be shipped due to the solvent in the product so ordering it online from the USA was out, I just gave it a go as in the past I had read on the forum of folks using their homemade versions with good success and spending a good deal less $… You know how the Kiwi $ trades against the $US… {:~/
I have used the same method as you with the Imperial but having to clean the case neck afterwards is just an added task that I just as soon avoid…
The Isopropyl alcohol from the chemist or Bunnings and a puffer bottle of ultra fine lock lubricant is a lifetime supply and it dries so quickly that the case can be mandreled virtually immediately, no mess, no cleaning up afterwards and remains just enough to give a notable ease of seating effort when seating bullets.