I have some cases with soft heads (they are new, from a now-defunct manufacturer). They do not handle even low pressure loads without excess pressure signs. It is not the gun. It is a wildcat round and these cases are properly headstamped. Is there a way to harden the brass in the case head area? Thanks.

Steve

NO; smash them with a hammer so no one can use them.

DEFINITELY...DO WHAT TOM SAYS...YOU ARE PHU***** around with a stick of dynamite.

You can SOFTEN brass in various ways and you can WORK harden brass case mouths and for a certain distance down the case wall...BUT YOU CAN'T harden case heads using home made methods without screwing up other portions of the case...BESIDES YOU HAVE NO WAY TO DETERMINE THE ACTUAL BRASS FORMULA. Most cases are made by impact extrusion or drawn...a giant hammer pounding brass into extrusion forms or squeezed/drawn in a many step process and the brass formula is designed to harden to specific hardness.

You didn't say what PRESSURES you were reloading to and WHY you thought the heads were soft. It's relatively simple to overload a case ahd have it produce expanded primer pockets, stick in the chamber or extrude into the bolt face.

WHAT IS THE REST OF THE STORY YOU LEFT OUT?

Good Hunting

I left out a lot because it doesn't change the question. But to provide a thumbnail of just a few relevant parts of the "story" which may be illustrative, and explain partly how I determined the case heads are soft:

Max. Avg. pressure for this cartridge is 63,000 psi. Load pressures are as low as 44,000 psi. Loads in the 53,000 - 55,000 psi range are easily handled by RWS and Norma cases but when loaded into the new cases in question result in the high pressure signs you indicated and others: difficult extraction, expanded primer pockets, expanded case heads, brass flow into the bolt face, fired cases rechamber with difficulty or not at all, and difficult resizing. There is not brass flow into the neck which would result in excessive release tension and high pressure. The shoulders were not set back when the bullet was seated. Loaded rounds chamber easily. These cases have not been neck/shoulder annealed (some of the RWS and Norma cases have been) so heads were not softened by improper annealing technique. The cases are new and formed (by me)
from the manufacturer-supplied tubular basic cases with correct head dimensions. Load pressures are lab established in a pressure barrel.

Bad brass is not worth wasting time with.

We have so many wildcats, not a single one of them has brass, but we make the cases from known quality parent cases.

Work harding? By firing and sizing?

Your new brass has a different volume than the 2 other brands? Does the new brass weigh more?

Loaded round neck diameter to large for the chamber? Pinching the bullet in the case? How about a donut?

Wildcat using Quickload data??

I am sure you know all this, just checking.

modulus of elasticity- Cartridge Brass-
Material is 70 copper/30 zinc with trace amounts of lead & iron , called C26000. Material starts to yield at 15,000 PSI when soft (annealed), and 63,000 PSI when hard.
Material yields, but continues to get stronger up to 47,000 PSI when soft, and 76,000 PSI
when work hardened. Modulus of Elasticity is 16,000,000 PSI. This means to pull a 1.000 inch long strip to 1.001 inch long induces a 16,000 PSI stress.
So if you pull a 1.000 inch strip to 1.005 inch long, you get about 76,000 PSI, which is the max obtainable.

quote:

Originally posted by 243winxb:
Work harding? By firing and sizing?

Your new brass has a different volume than the 2 other brands? Does the new brass weigh more?

Loaded round neck diameter to large for the chamber? Pinching the bullet in the case? How about a donut?

Wildcat using Quickload data??

I am sure you know all this, just checking.

Those are excellent questions. Case volume is very close on all brands of cases, as is weight. Loaded rounds chamber easily and each case neck is checked before every sizing to ensure that there is no brass flow which creates a donut at the bottom of the neck which pinches the bullet. When found, those cases are inside neck reamed. Load data was established in a pressure barrel using cases formed from RWS brass.

quote:

Originally posted by 243winxb:
modulus of elasticity- Cartridge Brass-
Material is 70 copper/30 zinc with trace amounts of lead & iron , called C26000. Material starts to yield at 15,000 PSI when soft (annealed), and 63,000 PSI when hard.
Material yields, but continues to get stronger up to 47,000 PSI when soft, and 76,000 PSI
when work hardened. Modulus of Elasticity is 16,000,000 PSI. This means to pull a 1.000 inch long strip to 1.001 inch long induces a 16,000 PSI stress.
So if you pull a 1.000 inch strip to 1.005 inch long, you get about 76,000 PSI, which is the max obtainable.

This is very interesting and helpful. It also may explain an observation I've made on the cases in question. I keep careful and extensive notes on all my reloading. I've observed that when newly formed and loaded, the cases in question do not handle much pressure, as explained in the beginning. But, I have a batch of them that, after 7 loadings of low - moderate pressure, annealing the necks and shoulders every 2 firings, they handle pressures near the upper end, although I don't max load them.

My initial intent with that group of cases was only to work up the loads in them a grain or two at a time from starting. The notes on the increasing ability of those cases to handle higher pressures was an unexpected observation. I hypothesized that it could be either work hardening by repeated firing/resizing, or perhaps a variance in the properties of the brass in cases from that manufacturer, or - something else I wasn't aware of. I haven't done the experimentation yet to try and figure it out.

Your information leads me to believe that there may be some work hardening going on from the repeated firing/resizing of those cases.

Thanks.

quote:

Originally posted by Steve up North:
Case volume is very close on all brands of cases, as is weight.

And then there's the case of Norma and their 300WM cases.
The early ones (pre '95 i think) thin as condoms and bulging was the norm(a). They beefed up the cases and wham would'nt you know it, some reloaders used old loaddata in new brass with way smaller internal volume and high pressures came out of nowhere (kinda).

So in short not all cases are created equal and for the 300WM +-3% case volume are the spread amongst manufactors now. And 3% is enough to go from hot to excessive.

quote:

Originally posted by The Dane:

quote:

Originally posted by Steve up North:
Case volume is very close on all brands of cases, as is weight.

And then there's the case of Norma and their 300WM cases.
The early ones (pre '95 i think) thin as condoms and bulging was the norm(a). They beefed up the cases and wham would'nt you know it, some reloaders used old loaddata in new brass with way smaller internal volume and high pressures came out of nowhere (kinda).

So in short not all cases are created equal and for the 300WM +-3% case volume are the spread amongst manufactors now. And 3% is enough to go from hot to excessive.

I didn't know that about early Norma 300WSM cases but when I said "all brands of cases", I was referring only to the 3 used for this cartridge. They vary just over +/- 1%, for a total range of about 2%; quite a bit different than the 6% range you give for 300 WSM. Definitely an important variable to check.