Brass sticking at all powder charges

[xsn10s]

Or I should say note where they say to measure expansion on the case head. The don't say to take the measurement on the rim.

 

[Pdvdh]

My understanding is the web and the rim is part of the case head. And when you measure for pressure you measure the area of the web for expansion.

The case rim OD and the primer pocket ID will also increase with excessive pressure, and can also be used to identify pressure caused expansion. I have verified this many times by direct measurements, pre- and post-firing of cartridges.

I agree, the case web is most common measure point referenced in literature. But when the web measurably and permanently expands, so do the case rim and primer pocket.

 

[Edd]

Otherwise we would have "case head separation".

That's just another term being used that isn't exactly correct. People know what you are talking about so it works.

You don't have "case head separation", you have "case separation". The case body separates just above the web because that is where the thin part starts.

I personally wish the term "Head" wasn't even used. I like to call it the base because it doesn't seem right for the head and the neck to be on opposite ends of the body. If the terms fit my logic, the bullet would be the head.

 

[Pdvdh]

Ask Hodgdon where the case head ends, and the case web begins. Is it 0.001" forward of the face of the casing? Or 0.200"? Or exactly what distance in-between those measurements?

And what term do they use to describe the face of the case that contacts the bolt face?

Many other manufacturers of cartridge cases refer to the case head as the location the primer is seated into.

 

[Pdvdh]

How about bald-topped case head? Now there's a term that eliminates any doubts, and many would completely understand from first hand experience.

 

[xsn10s]

I stand corrected, you guys are right. From the Hodgdon's article I posted. It seems I am rusty. "Lower pressure rounds, like the .30-30 Winchester, usually yield maximum pressures at .0003"-.0004" expansion. Modern cartridges, like the .223 Remington, will show maximum pressure at .0004"-.0005", while .308 Winchester, .270 Winchester, etc., typically yield .0005"-.0006" expansion at max pressure. Magnums, like the .300 Winchester Magnum, show maximums at .0006"-.0007" expansion, and should be measured on the belt. "

 

[xsn10s]

http://achievingadventure.com/blogs...artridge-ammunition-components-p1-cartridges/

 

[xsn10s]

The diagram I posted locate what is commonly called the case head. the descriptions you guys stated are what the saami definition are.

 

[xsn10s]

Where I was incorrect was the measurement of safe loads. Where I stated to measure is where the Hodgdon's location is. I was wrong as to the amount of measurement.

 

[Pdvdh]

.004 as the measured difference between a virgin case and a fired. When I measured the fired and sized case the change was more like .001

Then I think you're measuring the side wall forward of the case web at a location that commonly expands upon firing, and is swagged back down in the resizing die.
Less would seem preferable for less wear and tear on your casings. I don't really know from first hand measurements what is most common or normal at that location, just forward of the thickened web.

 

[Edd]

Then I think you're measuring the side wall forward of the case web at a location that commonly expands upon firing, and is swagged back down in the resizing die.
Less would seem preferable for less wear and tear on your casings. I don't really know from first hand measurements what is most common or normal at that location, just forward of the thickened web.

Measuring in front of the web doesn't tell you much about your load. I does provide good information about the chamber size. What is "normal" would depend on the difference between the size of the brass and the size of the chamber. The case could easily expand .004" in that location with a safe pressure load.

 

[Pdvdh]

Where I was incorrect was the measurement of safe loads. Where I stated to measure is where the Hodgdon's location is. I was wrong as to the amount of measurement.

Well Hodgdon is not speaking with a sharp tool or tongue, because they also state a 0.0001" capable measuring instrument "must" be used when monitoring case web expansion. And I've successfully measured and monitored case web expansion on 500-1000 casings over the years using nothing more than a quality 0.001" dial caliper.

The Hodgdon author either needs reading glasses, or he actually believes it necessary to identify 0.00005" case expansion. Why? For what purpose?

When even case head expansion up to 0.001" has never led to death or dismemberment. Things don't even start to get 'interesting' until 0.002" case web expansion, and all that will do is shorten primer pocket life. When you blow a primer loose from the pocket, you'll be at more than 0.004" case head expansion.

Hodgdon must make money selling 0.0001" measuring tools.

 

[xsn10s]

I don't recall Ken Waters measurements as being such either. And I have measured too many cases to count. But I'd rather say I was wrong when I find something like this on Hodgdon's website than to risk someone getting hurt because I was wrong.

 

[xsn10s]

My books are in storage from a move and i'm not about to go digging through them at this time.