Ever had brass that looked like this?

[Raven_Darkcloud]

Um.. The UMC in the Remington UMC stands for used military case. They are factory reloads. I have gotten a case like that and after tumbling it was fine. I wash, dry, size/decap, and then tumble. That gets me clean primer pockets too. You can still see some evidence of the lines after tumble but the case is still good.

[high standard 40]

Um.. The UMC in the Remington UMC stands for used military case. They are factory reloads. I have gotten a case like that and after tumbling it was fine. I wash, dry, size/decap, and then tumble. That gets me clean primer pockets too. You can still see some evidence of the lines after tumble but the case is still good.

I hope this was an attempt at tounge in cheek humor. UMC stands for "Union Metallic Cartridge" .......not used military case

[918v]

So you ran a dirty case into your sizer die? Don't do that. Clean your die. Clean your brass. Reload clean brass.

Please describe your entire reloading operation to us. I think you will benefit from our input.

[prs]

You were told to clean the dies, but not how to do it. My method is to wrap 0000 steel wool around a dowel to get a snug fitment and then soak that "swab" with Ballistol. Use and in-out and back fort rotation to polish the inside of the die and especially the size ring. Inspect under bright light and with a magnifier lens, repeat as needed to get it totally clean.

prs

[918v]

I use a brush soaked with solvent.

[Tom Herman]

All good advice... I can't emphasize enough on keeping things clean throughout your loading process: Remember that "garbage in" gives you garbage out....
I take all fired brass (whether stuff that I've fired, or gravel pit pickups) and agitate the brass with detergent and warm water.
Then, I wash it off about three times to remove all the dirt and detergent.
Next, I put the brass on a DEDICATED cookie sheet (only to be used for brass or bullets), and put in the oven at just about 225 degrees Fahrenheit (just above boiling). If you heat the brass too high, you'll soften it..
Once the clean brass is also dry, it goes into my Dillon tumbler which is filled with corn cob. I also add a teaspoon to tablespoon of their rapid polish, and tumble.
The brass comes out looking like new! It's also slick and offers minimal resistance to the reloading dies.
The stuff I produce comes as close to factory as you can get.
If you determine that you have a die that causes deep scratches, replace it.
Keep your cleaned brass away from grit and dirt. I had an issue where a rock tumbler that uses silicon carbide was near the reloading station.
One spill on the floor, and carbide went everywhere. I wound up carefully cleaning the area, and replacing at least one set of contaminated dies.
My casings come straight from sealed bins or bags onto a clean tray, where they are then reloaded.
If I drop any casings on the floor, they automatically are rejected and thrown into the next batch of shells to tumble.
Again, you can't keep things clean enough!
Best of Luck...

-Tom

[Shiloh]

Chamber looks rough as a cob.

Shiloh

[HangFireW8]

That case is a valuable lesson in how cartridges and guns work (and sometimes don't work).

The brass expands at peak pressure to fill, seal and grip the chamber, except where it doesn't- around the web. You can see that transition line clearly.

In a short recoil type gun, the barrel/chamber moves backwards with the brass for a short distance, allowing the pressure to drop and the brass to relax a bit. Then the barrel unlocks and the extractor continues the brass's journey backwards.

A clean, dry (as in not oiled) chamber is an asset to both good functioning and long brass life. A clean chamber allows the brass to both lock up with the chamber during high pressure, and unlock from it as pressure drops.

Dirty chambers act as lubricated chambers, stressing the locking mechansim on the gun.

[300winmag]

Might be the extra image sharpening that made it look that way. Its a really fine scratch and this round hasn't been reloaded. Literally just fired once, cleaned with Dawn and hot water, then rolled lubed on a pad, and de-primed on my press. Although when I first seen it I thought that too. I had to run a few dummy rounds through my magazine to see where it was scratching.

May I ask why you are lubing the brass if you are using carbide dies?

[Grump]

Longitudinal scratches provide nice origination points for longitudinal cracks.

Had a batch of .357 Mag stuff with maybe 1/3 that density of scratching and they started cracking on the 4th reload, about a third of them were gone after the 5th reload being fired.

But for THIS loading, no problem.

[jonp]

Thank you for the advice. I'll give them a good cleaning. I don't recall ever cleaning them when I got them.

I always de-prime them if they are not new and not mine (range brass, stuff someone gave me, etc) in a lee universal de-primer, clean and then run through the sizer.

[jonp]

May I ask why you are lubing the brass if you are using carbide dies?

I usually use some one shot on them out of habit. Maybe every 4th or 5th one. If they have been used a bit I put them in a gallon zip-loc, give them a blast and roll em around before sizing and loading. Just make them easier although it is not needed.

[243winxb]

Us your digital camera's macro mode. Clean chamber, change brand of ammo.

[429421Cowboy]

I hope this was an attempt at tounge in cheek humor. UMC stands for "Union Metallic Cartridge" .......not used military case

My thoughts as well...

[mdi]

Yep, good photo. If as you say, this is how the brass appears after firing and cleaning, I would say the gun's chamber is scratching the brass as it's extracting the case. FWIW; for about 12 years I cleaned my brass with a rag dampened in mineral spirits as I inspected it. Nope, my dies didn't wear out, didn't scratch my brass, and yep, I could see any defects as I inspected each case. Most dies available today are much harder than brass, and very difficult to "embed" grit, even steel. It does happen, but with the least common sense, it's very rare...

[jonp]

I hope this was an attempt at tounge in cheek humor. UMC stands for "Union Metallic Cartridge" .......not used military case

I hope it wad tongue in cheek too

[Iron Mike Golf]

I think its a resizing issue, not a chamber issue. The bad scratching stops about where the carbide ring stops and that zone is uniform around the case. If it was happening in the chamber, I'd expect the abrasion to go clear to the extractor groove.