45 Colt split case: Likely Bad Brass, not pressure problems (8gr Unique, 250gr LRNFP)

[Odd_Ball]

When I said brass flow I was referring to the case head. On a rifle you will see marks left by the ejector when pressures are at the yield level. You won’t see any marks left on the case head at 14kpsi.
I’m not concerned with case growth. Paper clip trick? Clean the case and inspect is visually. It’s a straight wall case

Ok, now I think I see what you are getting at in terms of pressure signs in this context:

• The ejector leaving a "stamp" on the case head/head stamp = pressure signs.
• Or perhaps even the striations/machine marks on the breach face leaving an imprint on the case head/head stamp = pressure signs. (I think I read this one in Lyman 49th ed.)

Again, with understanding this would be on rifle or other load developing pressures to the brass yield levels, not standard 45 colt. Much oblidged for all the feedback here.

I keep two batches of brass in 45 colt. Rifle brass and pistol brass. I anneal my rifle brass as it helps seal the chamber on a 1873 rifle. This keep the fouling to a minimum on the gun. I’ve not had a need to anneal for the pistol though.

Good to know, thanks!!

[kcstott]

Ok, now I think I see what you are getting at in terms of pressure signs in this context:

• The ejector leaving a "stamp" on the case head/head stamp = pressure signs.
• Or perhaps even the striations/machine marks on the breach face leaving an imprint on the case head/head stamp = pressure signs. (I think I read this one in Lyman 49th ed.)

Again, with understanding this would be on rifle or other load developing pressures to the brass yield levels, not standard 45 colt. Much oblidged for all the feedback here.



Good to know, thanks!!

You would be very lucky to be able to see the imprint of the breach face tooling marks in the case under field/range conditions. What’s often seen is a slightly raised shiny semicircle from the ejector. Or on a Mauser a slightly raised line from they ejector slot. You exceeded the yield strength of the brass when this happens and as you rotate the bolt to open the action a smearing effect leaves those raised areas with a bit of a shine.

It the reason I laugh when I hear guys talking about “looking for signs of overpressure” on handgun loads. As if the brass is going to react differently due to being loaded in a pistol.
That said there are quite a few semiautomatic handguns that leave a area of the case wall near the head unsupported. If this area swells you area exceeding the pressure limits for the cartridge and firearm design. Which is why the 45acp is a 20kpsi round max. The Colt Single Action Army is a 8-10kpsi firearm even though modern brass can tolerate six times that pressure.
This is where firearms design strength is the limiting factor and why your 49th edition Lyman book has loads for different firearms. Like Trapdoor Springfields, Tompson contender pistols, and ruger #1 loads all due to the strength of the firearm being used.