factory shells swelling?

[flyinpolack]

Hi, I'm new to reloading & I'm setting up to do 9mm. I used to reload with my dad years ago, but I'm getting my own thing going now.

I've been visually inspecting my empty shells & some of them are bulged .003-.006" about 1/8" from the groove at the bottom. Are these shells useable, or should & just toss them?

I probably have 5000 rounds worth, so I don't need to save anything that isn't 100% safe

Also, how large of a dent or ding in the brass is allowable? my friend's glock beats the hell outta the brass.

Do you guys clean the brass before depriming, or after?

Thanks for any input!

[darkgael]

I clean my brass before sizing/depriming. I want to avoid getting any dirt or debris into the sizing die.
The bulging - clean and size a few. See if they come back to spec. Cases that have been fired in an unsupported chamber may have bulging. Also, abnormal expansion of the case head, beyond 0.0005" is one indicator of loads that were too hot (although that can and does occur with factory loads.)
I'd would ditch any case over 0.0005".
Pete

[SL1]

flyinpolack,

Cases typically bulge when fired, then spring-back a little, which makes them more or less shaped like the chamber, but just a little smaller so that they eject easily. Where the brass in the cae wall gets thicker near the base, it does not spring back quite as much, and the really thick and solid parts expand very little or not at all, leaving a section called the "pressure ring" in the thick part of the wall that is the maximum diameter for the fired case. How big the pressure ring gets is primarily a function of how large the chamber was where it was fired, which can vary substantially from gun-to-gun, and even among the different chambers in the same revolver cylinder. And, it is not abnormal for the pressure ring to be not exactly round, for several reasons. A little out-of-round isn't a problem. Some pistols (most notoriously older Glocks in .40 S&W) have a section of the back of the chamber cut away to aid in feeding, and the case typically expands a lot in that area, making a "guppy belly" in that region. Some folks throw those away, and some resize and shoot them. There is even a special resizing die that is made to get the "guppy belly" completely out of the case, so that tells you there is a demand for such a thing from a lot of shooters.

If you have a Glock or other gun with a chamber that makes large guppy bellies in your cases, you probably should be concerned that repeated resizing and firing them could prematurely weaken the brass in that area and lead to a case failure (which is at best unpleasant and often damaging and injurious). On the other hand, if you shoot a gun with a good supporting chamber, taking the guppy belly out of a case that has been fired once in somebody else's Glock should not be dangerous in your gun.

Do not confuse what darkangel said about 0.0005". He was talking about expansion in a different place on the case. He was referring to the case head area, which is the area just in front of the extraction ring, where there is solid brass (except for the flash hole). That might expand some on the FIRST firing, depending on hardness of the brass in that area as much as the pressure of the load. But, that first expansion work-hardens the brass, and it won't expand again until it experiences significantly higher pressure. I have some Speer .357 Sig case that expanded 0.0008" when fired with the factory load, which should be a little below 40,000 psi, and some Winchester .270 Winchester brass that expanded only 0.0002" at a load that should have been over 60,000 psi. SO, case head expansion is not a very good way to get an accurate pressure reading. And, you would need to know what the case dimension was BEFORE it was fired to get the difference, because cases do not have outside dimensions that are right at the SAAMI maximum spec. to begin with.

And, as for case cleaning, another approach is to get a "universal decapping die" that ONLY removes primers, and use that before cleaning the cases. That allows the cleaning process to remove residue from the primer pockets, and keeps even more of the crud away from your other dies. Primer crud has powdered glass in it, which makes it abrasive. I use a cheap Lee "C-type" press for my decapping die, so that keeps the primer residue, as well as the range dirt and powder residue out of my good press and dies. I did not worry too much about cleaning cases when I was only shooting bolt guns and revolvers, because my brass never hit the ground and I just wiped it clean and used a brush-like tool on the primer pockets. But, when I started shooting auto-loaders, especially for IDPA events, my brass was going into the mud and being raked-up. It was filthy and I didn't want it anywhere near my press and dies until it was cleaned AND INSPECTED for embedded grit. Also, auto-loaders are intrinsically more finicky about loads as well as more damaging to brass than revolvers and bolt-actions, so I needed to really step-up my brass cleaning and inspection processes to make reliable ammo for them.

SL1

[flyinpolack]

Thanks for the info guys! I"ll just shelf that brass until I find one of those dies.

Also, here's a little test that I did: I noticed that a lot of the "bulged" ammo shells were federals. I've been buying the american eagle brand of Federal ammo from a local gun shop, along with some federal "champion" ammo from wally world. I have a sig & my shooting buddy has a glock. My buddy has only been using the "champion" ammo from wally world. I started noticing that his federal brass wasn't bulged like some of mine were.
They look the same by eye, the rim dimension & bottom dimension , height & everything so I weighed them.
the wally world brass (champion) shells weigh 60 grains
the american eagles weigh 54 grains.
weird, eh? I would have thought the wally world stuff would be lighter