What are the signs of high preassure in straight wall handgun cartridges (454 casull)? I ask this because different loading data sometimes gives different maximun powder charges when using the same bullet. Thanks.

I never push the limits in any of my guns but I have a couple loads that I felt were getting toward the high end for a specific SA revolver (44 mag SBH). This was due to the case having slightly more resistance on extraction.

I believe most .454 Casull data out there is well below the 65,000psi SAAMI maximum. Its hard for me to say that definitely since most data lists CUP, not psi. That could explain some discrepancies if one manufacturers data reaches slightly higher pressures than another.

Its not unusual for a powder manufacturer to have different min and max charges than a bullet manufacturer lists using the same bullet/powder. It can cause some confusion and uncertainty.

Flattened primers, sticky extraction.

Extraction issues extend to the cases you use. Winchester 454
cases are much harder than typical handgun brass. In casewall
deflection tests done as part of calibrating our pressure barrel, the
Winchester cases needed 5,000 psi more pressure to deflect the same
amount as the Starline cases, which showed a hardness consistent
with most magnum handgun cases. From SPEER Lab Notes for the 454 Casull

As Sawfish noted above cases of different hardness will display different degrees of sticky extraction with hot loads. Soft brass will also have loose primer pocket show up before hard cases will.

You will have this same problem with primers. Softer primers (Federal) will flatten more/sooner than Harder Primers (CCI).

So if you are loading with soft shell cases, and soft primers you will have pressure signs show up at lower pressure that you will with harder cases and harder primers.

Next issue is loading data being all over the place in the manuals. One manual may list a maximum load several grains higher or lower than another manual. AS noted above, this makes establishing a Maximum Safe load more of a challenge.

Next issue is loads listed on the internet. I have two 357 Maximum single shots. The loads I am using in both are quite a bit above Book Loads, which I suspect are on the conservative side just in case one might find its way into a revolver. My CVA Scout which strength wise is about like my Encore will take a load that will unlock my Contender. The point here being a load that appears safe in one gun, may be way too hot in another. When working up my 357 Maximum Loads, I found some on the internet that were TOO HOT in my guns. NOTE I always work up from below establishing maximum loads. Do not just jump in and use a maximum listed load, work up to it.

On the other hand you can find work ups on the internet listing all components used that can be very helpful working up your loads.

When I work up a load I will start watching my primers first. You need to watch for flattening and cratering. Sticky Extraction is another pressure sign to watch for. Loose primer pockets normally means start backing the loads off.

Another issue is temperature. You can work up a Maximum Load in January that will blow primers in July. Normally I am very busy during the warmer months. I have more time to work up loads in the Winter. Something to keep in mind.

One last thing is case lube. You do not want any lube on your shell cases that are loaded. Not normally an issue with carbide dies.

The more reloading that you do, the easier it will be to work up loads.

Bob R

The three primary things I look for:

1. Flattened primers. If the primers look flattened at the edges, it's a sign that the pressure is pressing the cup of the primer against the face of the firing pin housing. The only problem with this is different primers' cups are harder or softer than others. Still, if your warmer loads are flattening your primers noticeably more than lighter loads, it can be a pretty good visual indication of where your loads are.

2. Sticky extraction. If the case doesn't come out as easily, it's a sign that the pressure is expanding it and pressing it against the side of the chamber, increasing friction. This is generally the sign I strive to stop short of.

3. Blown primer. If you've got gas leaking out from around the cup of the primer, or especially if the primer indention has blown out, I stop shooting and figure out what's gone wrong. Sometimes you might have a bad primer, but if you're experiencing other pressure signs then get a blown primer, it's probably best to stop and reevaluate your loads.