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-   -   Not so dumb dumb question: Short Brass (http://www.firearmstalk.com/forums/f30/not-so-dumb-dumb-question-short-brass-80044/)

Patrick Sperry 01-02-2013 01:23 AM

Not so dumb dumb question: Short Brass
 
I have been loading / reloading for a few years now but consider myself still pretty new to it. Hence, I am asking this because the kid across the street is just starting, and asked it of me. Well folks, I simply didn't know!

He is loading for two rifles; A 270 and a 45/70 as well as a 45ACP. The 270 I can help him with. But the straight walls..? Well here is the situation, and question.

He bought new brass, all Remington in the bag. Good so far, but..? It's all way shorter than minimum published length. It is also a bit off square at the mouth. Should he run it through his dies, and then do a minimum trim to square? Even if it is already "short?" (He already ran the 45/70 through the sizer.) Would the 45 ACP be treated any differently? Then he asked me about de-burring. Just how much is enough? I told him to just smooth off any burrs, and not to make it a "sharp" shoulder. Was I correct? I realize that is subjective however if there is a definitive answer that would be great. This kid is doing liquid division at fifteen...

Hmm... Stopped posting to go and check something. All of my brass, the new stuff, is way short, all of it. Remington, Winchester...

270 Win, 35 Whelan, 357 Mag, 9mm, 10 Auto, 45 ACP, 357 Mag, and 45 Colt! Perhaps this isn't all that a silly question!

Any help would be greatly appreciated!

blucoondawg 01-02-2013 01:57 AM

The 45/70 is a rimmed shell so the shell won't be headspacing on the case mouth, most people I have asked about this say you generally won't have to trim straight walled shell casings as they won't stretch much, a 45 acp head spaces on the case mouth so if the case is shorter it will allow the cartridge to slide slightly farther into the chamber, the main thing to worry about is the overall length of the round with bullet seated, by compressing the bullet farther into the casing than the overall length specified you can change the pressures. Most people don't bother trimming the straight brass unless they are seeking uniformity for ease of roll crimping. I am somewhat anal about my reloading so I would trim if it were growing above the trim to length but if it is a little short it should be fine, like I said watch out for that overall length. Also check a couple different sources for specs, some manuals use different numbers, what is a couple thou short in one guide could be right on in another.

Patrick Sperry 01-02-2013 02:01 AM

Thank you! I was thinking that but..? As stated, I am new to the field.

c3shooter 01-02-2013 05:31 AM

Is the length you are looking at the Overall Length (OAL) which is the length of a loaded CARTRIDGE, and not the case length???

Sport45 01-02-2013 07:54 AM

If they're less than max I wouldn't worry about the .45acp or the .45-70 brass. In fact, I wouldn't have bothered to even measure the pistol brass to begin with.

He could square up the mouths on the.45-70, but I doubt he'll see a difference on the target.

Straight wall cases don't stretch much with use and sometimes shrink.

Patrick Sperry 01-02-2013 01:58 PM

Quote:

Originally Posted by c3shooter (Post 1075887)
Is the length you are looking at the Overall Length (OAL) which is the length of a loaded CARTRIDGE, and not the case length???

The case length, sorry. I should have made that more clear.

robocop10mm 01-02-2013 03:08 PM

It depends on the numbers you are referencing. Max case length is just that MAX. Most cases call fro a "Trim" length that is .010" shorter than max. There is considerable variation allowed in some cases. .45 ACP is VERY forgiving. Take a case and drop it into the firld stripped barrel of the intended gun. The base should sit at or slightly below the "hood" of the barrel. The hood is the squared piece at the top of the chamber end.

Are you sure your measuring instrument is accurate and properly zeroed

JTJ 01-02-2013 03:30 PM

As an example: I am prepping a bunch of 9mm. Max oal is .754" while Min oal is .744". I am getting a .003" gain on resize. New cases are measuring .748". I am culling cases under the min and trimming cases over .750" to .748" to keep the crimp somewhat consistent even though I am using a taper crimp die. I dont like roll crimps and I would make the cases more uniform if I had to use one. Get seperate taper crimp dies if you dont have them.

locutus 01-02-2013 06:51 PM

We have been told for generations that .45 ACP head spaces on the case mouth. In reality, it head spaces on the extractor.

I've loaded and fired many, many .45 ACP rounds that were as much as .025 short, and they worked as well as any other brass,

Load 'em up and try 'em!:)

Patrick Sperry 01-04-2013 12:36 AM

Quote:

Originally Posted by JTJ (Post 1076212)
As an example: I am prepping a bunch of 9mm. Max oal is .754" while Min oal is .744". I am getting a .003" gain on resize. New cases are measuring .748". I am culling cases under the min and trimming cases over .750" to .748" to keep the crimp somewhat consistent even though I am using a taper crimp die. I dont like roll crimps and I would make the cases more uniform if I had to use one. Get seperate taper crimp dies if you dont have them.


Thank you! That is what I / we were looking for.
:D


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