Hair like strands of brass off a roll crimp?


March 9, 2013, 05:19 PM
Hey guys,

I have a new set of RCBS .357 carbide dies. I loaded 5 boxes of .38 special, 158 grain copper plated (Berry's) and then decided to switch to .357.

I am loading 125 grain Speer SJHP with Federal .357 Brass. I set the dies to roll crimp against the bullet cannelure. The results look good and can see a slight crimp against the bullet. The overall length is right on.

What I noticed and I mean barely noticed is very fine strands of brass hair coming off the crimp of the finished round. These are very fine with one strand per bullet that is about 3/8" to 5/8" or so in length.

You guys seen this before? Is this normal?

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March 9, 2013, 05:23 PM
Did you trim the brass? Could be leftover from that process.

March 9, 2013, 05:34 PM
Did not trim the brass. Will try to get a picture.

March 9, 2013, 05:57 PM
That happened to me once. I flared the case mouths too much.

March 9, 2013, 06:01 PM
The three on the left have tiny brass hairs, hard to see on far left. Second from right does not. Far left is factory Remington 125 grain SJHP for comparison to my rounds.

My OAL is 1.590 inches. 15 grains of 2400. Remington small pistol primer, with federal cases and Speer 125 grain SJHP. Roll crimp

March 9, 2013, 06:53 PM
It is not unusual with new brass or trimmed brass. A slight chamfer on the outside of the case will usually stop it. If the brass was trimmed it is a must to chamfer it, as well as deburr the inside of the case mouth. The good news is the next time you crimp those same cases it probably won't do it again. That is assuming the crimp is not excessive, and it doesn't look like it is.

March 9, 2013, 07:08 PM
Chuck that ammo in your tumbler with clean media for about 5-10 minutes and it should all come off. Works for me.

March 9, 2013, 07:14 PM
Chamfer & debur the brass inside & out.


March 9, 2013, 07:16 PM
I had "hairlike slivers of brass" coming off my full length sizing die for 223. Know what I had in common with your setup? Federal Brass.

I can load LC, Rem, Win, and PMC all day long, no problems, but when I switch to FC brass, about 1/3 of it gives me slivers that look like 2/3 of a ring. I took some advice and started chamfer/deburring the cases prior to resizing (in addition to the cham/debur after case trimming, after it's been sized, if needed).

The downside is, i have to cull about 1/3 of the brass that way, because if the case mouth is not round, you cannot chamfer/debur it without taking too much off one side and not enough/any off the other. You will just grind down the ding/bend in the neck that would otherwise be trued when the sizing ball passes through with the sizer die.

Then again, handgun ammo tends to not get dinged up as much as 223 from an AR platform, so your experience may vary.

Here are what mine looked like:

March 9, 2013, 07:18 PM
because if the case mouth is not round, you cannot chamfer/debur it Why would the case mouth not be round after sizing it??

I chamfer & debur after resizing.


March 9, 2013, 09:38 PM
Yep. Size, trim if needed, deburr and chamfer.

March 9, 2013, 09:56 PM
The occasionally still-not-round-after-sizing case happens when there's a significant flattening of one side. You can fix it by flaring the case ever so slightly after sizing (the expander button does the job of rounding) then sizing again or by hitting a flattened case mouth lightly with the expander die before sizing. Voila!

March 9, 2013, 10:45 PM
I get those on occasion when reloading my .357's but I never really worried about it since they all seem to shoost just fine, YMMV.

March 10, 2013, 11:39 AM
I got them when I first started but it was from over flaring.

March 10, 2013, 01:34 PM
Why would the case mouth not be round after sizing it??

I chamfer & debur after resizing.

I chamfer and debur after resizing as well, and have no problems with that. Some AR's put a healthy ding in the brass neck from the extractor (not mine, but range brass I find).

The issue I ran into with FC brass (federal) in 223 is that I could size it, but I was getting those slivers coming out of the sizing die. Talked to Redding (maker of my 223 dies) and they suggested chamfer/debur before sizing as well.

The problem with that, is those neck dings preclude that, you just grind metal off the dinged side and nothing happens on the other sides.

It was either grind the ding before sizing (bad) or size first and get slivers (not as bad) then size again after trimming.

I think the ideal option would be to have a throat sizing die that does not size the case, just the neck, expand it out to get rid of dings, chamfer/debur, size the case... but then you are working the case mouth more than is necessary and could shorten the life of your brass (which is pretty short with Federal brass as it is).

March 10, 2013, 05:47 PM
I trim, ream & chamfer all my brass and I still get a few that will get those hairs now and then, just not as excessive as what your getting. I occasionally get one tiny hair right on the crimp.


March 10, 2013, 07:23 PM
I've had it happen with freshly prepped, trimmed/chamfer/duburr, brass on it's first loading. Doesn't happen after the first time. I've never worried about it.

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March 11, 2013, 12:03 AM
I had the same issue with Lee FCD's. I took the die apart and found out that in the machining process to cut the die, they ran the lathe too fast and actually cut a spiral groove all around the inside of the crimping surface. I polished it as much as I could and improved it, but they still peel a very fine sliver of brass from the outer surface of the case mouth.

I sent an email to Lee about it, and they basically blew me off. They know about it and apparently don't find it enough of an issue to correct it. And the bad part is, every one of my FCD's have the same issue.

Look at it under very strong magnification and if you have the same problem it will be obvious.

March 11, 2013, 12:06 AM
All new brass has a burr left from the final trimming that must be removed by the consumer. Once you deburr it you will not have the "shavings" any more. If you trim the brass it will have the same burr. You have to remove it.

March 11, 2013, 04:46 PM
If you are seating and crimping at the same time it probably is shaved copper from the bullets, not the case. Deburr the case mouth. They will shoot, but be a partially jacketed bullet.

March 12, 2013, 06:25 AM
That happens to me all the time when chamfer and deburr 45lc. Its no big deal, when you roll crimp your actually pushing the case into the bullet, hence "crimp" when you [urt the ram down to accuire your loaded case, the crimp has pushed you expanded case into the bullet, so there will be a little hair strand there.

No worries, load and go.

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