Dimples on shoulder after resizing 5.56

[Gabe1519]

Sorry I don't have any pics for you guys yet but I noticed small dimples appearing on the shoulder of some 5.56 brass I've been resizing. I'm using the rcbs small base die set and I don't use too much lube on the cases (at least I think I don't). The dimples appear all around the shoulder being approximately the same size. It doesn't seem like some that would affect chambering and they would most like be pushed out upon firing. Is this something you have seen before on 5.56 cases?

Another question beside the main point. Are 5.56 cases supposed to be resized in .223 dies? I've never heard of a special die for 5.56 and I'm guessing it's ok to resize, may take a bit more trimming though since the cases are a tad longer. That's the only difference I've noticed on the 5.56 cases is their length. All other dimensions appear to be the same. Also, one other annoying question. Are all 5.56 cases considered "military brass"? I noticed seating primers in them are tough as well after cleaning out the pockets.

[rg1]

Possibly a piece of dirt, powder, or brass flake is sticking to your sizing die and leaving small dents in your shoulders? 5.56 and .223 brass are identical and use the same dies. Main difference in military 5.56 cases and commercial cases is the primer pocket has a crimp that needs to be removed in military crimped primer pockets.

[Gabe1519]

Well I would suspect something was stuck in the die except that when I resize .223 brass it comes out just fine. It only happens on a handful of 5.56 cases. Out of 100 5.56 cases, about 10 of them had the dimples. I checked the dimensions using calipers and they check out just fine with other cases that resized ok. Probably nothing to worry about as long as it chambers fine. A few of my first reloads have primers seated about .013 below the base and I think that might be more of an issue than the dimples.

[Gabe1519]

image.jpg

Hope y'all can see the attachment. It's barely noticeable in the photos but are a little more prevalent in better light.

[FrankenMauser]

It's not likely to be the problem, but make sure the vent hole in your die is not plugged. It's a small hole (about 0.060"), at the same height, from the base, as the case shoulder. Just shove a paper clip through it, and then make sure no debris ended up inside the die.


Other than that possibility, it looks like a little too much lube - not much, but enough to build up in the die and cause the occasional dimple.

I wouldn't worry about it, though. You don't want to use too little lube, and stick cases. And, those dimples aren't really an issue. So.. I'd keep doing what you're doing. The dimples will blow out when you fire the cartridges.

[Blindstitch]

I would clean your dies and try again. I was putting dimples in 30-30 brass and I thought I was lubing it lightly. Then I talked to some guys and did some testing and I can now resize dimple free brass. Turns out I was using 2-3 times what was needed to do the job.

With the lube a little can go a long way depending on what type you use. Another effective test would be to see how little lube you can put on till it feels like the brass is getting stuck. And then increase a bit.

As FrankenMauser says don't worry those dimples with blow out.

[Old Stony]

Certainly looks like an excess of lube problem to me.

[mehavey]

- Excess Lube on the shoulder. (The case needs almost no lube anywhere even near the shoulder.)

- Yes, they will simply fireform out normally.

- Yes, 5.56 and 223 are identical as far as cases go. Trim all to same SAAMI spec of 1.76"(MAX)/1.75"(Trim-To)

[Gabe1519]

Cool, thanks guys!

[SWThomas]

Make sure you check them before you size them. I've had a couple I wondered about and it turned out they had those dents before I sized them.

[pete2]

Excess lube will do this.