Reading Lyman 49, have a question...

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Great Crouton

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I'm in the chapter re: reloading handguns cartridges, in particular the case triming section. Sorry, I should have copied down the page number so anyone with a Lyman 49 can see what I'm getting at. Thers is a paragraph that says: (my comments are the italic text in brackets, see the end of the paragraph for the sample data they show on the next page)

IMPORTANT: Case length of rimless, straight cartridges is critical for proper ammo headspace. Be certain that such cases stay within the listed trim-to(.888" according to the sample data on the next page) and maximum cartridge lengths(.898"). It is not uncommon to find new or once fired pistol cases that are shorter than our listed trim-to length. If your cases fall into this category, they have likely been manufactured to the minimum acceptable case length. Cartridges that head-space on the case mouth usually have a minimum case lenth which is .010" shorter that the maximum allowable length. While not offering as precise head-space fit as longer cases, they will be functional and safe to reload as long as they do not fall below this minimum lenght.

On the next page they have a sample data that shows a trim-to length of .888" while the diagram of the cartridge above shows the total length of the case to be .898 which I think is the max?

While not offering as precise head-space fit as longer cases, they will be functional and safe to reload as long as they do not fall below this minimum lenght.
Click to expand...

This is the line that is confusing the heck out of me, what is the length they are getting at here?
 
Many new manufacture cases are below minimum listed case lengths. I have had bags of cases that te trimmer didn't even touch. It doesn't mean they won't work, just that the headspace might be off a little. They will still go bang. The situation arises from manufacturing a cartridge that will be guaranteed to fit in ANY commercial chamber. Don't worry, you will soon be able to trim them.
Now that's only if they are like, a thou short. Any more than than, and you may get FTF's with those rounds since the firing pin won't hit the primers hard enough to fire them.
 
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Ok, so for the purposes of their example, if I come across a case that measures .887 or less, I should chuck it?

What I'm trying to determine here is what length they are getting at in this example as being to short.
 
Trimming straight-walled pistol cases is completely unnecessary. The trim lengths listed in manuals are a somewhat arbitrary number (e.g. .010" under maximum) rather than a SAAMI or CIP specified minimum. Don't worry if you have a few cases that are a little shorter than your manual's trim length.
 
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And that was basically my next question as I'm sure I read in the manual that most pistol cases wear out long before they need trimming so why the hell am I worrying about this? Lol...
 
Great Crouton said:
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And that was basically my next question as I'm sure I read in the manual that most pistol cases wear out long before they need trimming so why the hell am I worrying about this? Lol...
Click to expand...

gotta have something to worry about!

as stated trimming straight walled brass is a non issue.
 
So my calipers finally arrived last night so the first thing I did was measure all the spent .40 casings I had. Lyman manual says trim to .888, most of the brass I had measured in the .835 area I think (goin by memory here). Now obvioiusly all of this brass went through either my handgun or someone elses just fine but should it be reloaded? Amusing thing as well, I also got one of those go-no-go gauges and none of the other factory reloaded ammo I use fit in it at all. Seems to be a bit wide near the base. I'm sure in the past when I had the barrel out of my handgun, I dropped in a cartridge to see how it fit and it fit just fine, are those go-no go gauges junk? Lyman brand.
 
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