What Causes a Shoulder Crush?

[Silver Jack Hammer]

Or how do I prevent it? Resizing the .38-40, never had a crushed shoulder before. I've throughly cleaned the inside of the die. I've wiped the lube off the case. Now 100% of the cases are getting the very same crush indentation.202630

[Boolit_Head]

That looks strange, not like any shoulder crush I've seen before. That is usually from seating and crimping. This looks more like a hydraulic dent from case lube but you said you cleaned them. Am i seeing this right that is a crease fore to aft of the case from sizing? I am guessing during cleaning the die you inspected it looking for a obvious cause there.

Just on the outside chance have you checked case length to see if they need trimming?

[Silver Jack Hammer]

I've certainly inspected the inside of the die, sized, observed the crush, cleaned and inspected again and got the crushed case again. It's a real puzzler to me.

[Boolit_Head]

That is making me think there is excess metal in the shoulder that has to go somewhere. By chance got a case from a different batch? maybe it will act differently.

[Silver Jack Hammer]

These cases have been resized in these dies using the same lube without being crushed. Same components, new problem.

I've seen this kind of a crush on .270 cases, but only a small percentage of the cases were crushed. Now 100% of the .38-40 cases are crushed the same.

I'm duplicating the problem 100% of the time. It's a new problem I can't figure out.

[Silver Jack Hammer]

Forgive me as I blather on...

The .38-40 chamber doesn't support the shoulder so fired cases expand the shoulder forward and shorten the neck. Resizing the .38-40 reshapes the neck back to its longer specifications and reforms the shoulder back lower on the case.

I loaded these cartridges with very old 700X. The powder doesn't reach the same velocities as new 70X. I've loaded these .38-40 a little light because this old 700X may be a little unstable.

[Silver Jack Hammer]

Starline brass, Redding dies, RCBS pump spray case lube. Shooting lead home cast boolits of course out of a 3rd Gen Colt's SAA. The press is a Rockchucker.

[dubber123]

I am fairly certain I have seen dies with a tiny pinhole drilled in the shoulder area, and assumed it was there to relieve any built up air pressure on cases that may seal on the case body and neck simultaneously. Is there a chance your dies have this hole and it's plugged?

[Earlwb]

I was thinking that if all else is OK, then maybe it is the brass case stretching out over time from multiple shots fired. The metal gets more thin. Then when you resize it the excess brass has to flow somewhere and it causes the dent to occur.

[35remington]

Change how you are lubing the case. Appears to be clear sign of lube denting. Lube dents occur on the shoulder just as pictured.

[Silver Jack Hammer]

I'm using lighter fluid on a patch on a jag to clean the lube off the inside of the die and a terry cloth rag to clean the lube off the case. Still getting th the shoulder dent.

[17nut]

Never lube the neck/shoulder, only the base/cylindrical part of the case.
Wet a finger and swirl it around the base, thats all you need.

[OS OK]

Have you tried backing the size die out a turn, sizing and checking the case in a case gage? or your cylinder...
Maybe your pushing too much brass back and possibly too far. Could need annealing also.

[swheeler]

I'm using lighter fluid on a patch on a jag to clean the lube off the inside of the die and a terry cloth rag to clean the lube off the case. Still getting th the shoulder dent.

Does the sizer die have the vent hole as described by Dubber and is it plugged with old hardened case lube, a needle and some spray brake cleaner may fix it.

[Silver Jack Hammer]

I've eliminated the shoulder crush by twisting a lighter fluid soaked patch on a jag in the die. Previously I'd just run the patch up and down the die. It needed a more vigorous cleaning.

There is no vent hole. Thanks guys

[Silver Jack Hammer]

17nut, thank you

[gnostic]

I've seen similar crushed cases when sizing 223 military cases to 221 fireball. I'd back my sizing or trim die off a bit and see if the cases will chamber.

[mold maker]

In over 55 years, I've never experienced a dent like that, but will now know what to look for if I do.
That's how, even us seniors, learn and solve problems.
Thanks to all who contributed.

[Silver Jack Hammer]

I've been loading for 40 years, what's important is to have a source such as castboolits for when I've got a head scratcher. There's a certain amount of anxiety that arises when faced with the unknown along with damage to your components. Glad help is here.

I've cleaned the begebers out of the inside of the die with lighter fluid and thrown the cases back in the tumbler for an good cleaning and polishing. Next resizing session will follow 17nuts advice.

[Larry Gibson]

Are you sure there's not a vent hole under the lock ring?

That's where it is on my RCBS 44-40 FL die.

[osteodoc08]

Clean your sizing die and take it easy on the lube. Those will fire out.

[osteodoc08]

Never lube the neck/shoulder, only the base/cylindrical part of the case.
Wet a finger and swirl it around the base, thats all you need.

I'll add a touch of lube to the INSIDE of the mouth for the sizing ball when I feel it sticking a bit on the downstroke. Not needed every case. But agree with above.

[Silver Jack Hammer]

There is no expander plug in the resizer die, there is no air hole at the shoulder.

Resizing now after dousing the die in degreaser, running the brass through the tumbler and using such a minimal amount of lube I feel resistance unlike ever before, 95% of the cases did not have the shoulder crush, however there was a dimple on the shoulder of a few cases. This has never happened before.

[Tom W.]

I have had those lube dents when using RCBS lube and getting some lube on the neck and shoulder. I switched to Imperial sizing wax and stayed away from the shoulders and never had the problem again. The dents will iron out....

[Boolit_Head]

What lube are you using? I've had good luck with the Hornady unique case lube. Heard good things about imperial sizing wax as well.

[osteodoc08]

What lube are you using? I've had good luck with the Hornady unique case lube. Heard good things about imperial sizing wax as well.


I've used both and they're about the same.

[Tom W.]

I've had my can of Imperial for years and it looks as if has never been used.... and I know better...

[Boolit_Head]

I was specifically interested in what lube Silver Jack Hammer was using in this case.

[earlmck]

I don't know why you didn't have some shoulder dent problems previously -- the lack of a shoulder vent hole would seem to me to be causing much of your troubles. I just looked to be sure, and my Lee 38/40 die has the vent hole up about .875" above the bottom of the die.

I'd guess your occasional dents are because even when lubing only the bottom of your cases some lube migrates up toward the shoulder area and the lack of a vent hole makes things extra tetchy.

[Silver Jack Hammer]

I used RCBS Case Slick Spray Lube on the .38-40 without difficulty and rather liberally for over a year, now these crushed shoulder dimples. After a thorough cleaning I applied RCBS Case Lube-2 on the fingertips as per 17nut's recommendation.

Why this is cropping up now and not before when I cannot identify what's changed is a riddle I haven't unraveled yet.

[Boolit_Head]

Over time the lube must have solidified in the die.

[Silver Jack Hammer]

Over time the lube must have solidified in the die.

That makes sense.