Brass shavings from crimp--any idea why?

[mongoose33]

I'm trying to do a production run on my LnL AP progressive using my recently cast and powder-coated 9mm boolits. I've previously done a number of different combinations of powder, crimp, and so on to find the sweet spot--which I have found. It includes a final crimp with the Lee factory crimp die, a size for the boolit of .357, and an OAL of 1.100. It works in my XD, and is very accurate. There's a little swaging of the boolit, but not real bad, and the accuracy and reliability is excellent. It's a winner.

Except...I'm getting brass shavings from the mouths of the cases, and I cannot figure out why. I've tried both the Factory Crimp Die as well as a Redding taper crimp die, and they both do it. I've cleaned them and the Redding die has no rough spots I can discern.

At first, I thought maybe I was casemouth expanding just too much, but I've dialed that back as far as I can and still be able to start the boolit in the case.

Here are two pics; the first shows the boolit prior to seating, so you can see just how much casemouth expansion there, and after seating, where you can see there are no shavings or anything else. The second shows the shavings--when i run a few through, they accumulate in the die.

Any idea what's going on? Worn dies? A disturbance in the force? I'm just stumped.

148354148355

EDITED TO ADD: Problem appears to be solved--look to post #12 for what I found out.

[Der Gebirgsjager]

I kind of like the disturbance in the force idea......
Is the brass all the same brand, or a mixture?
Is it previously fired?
Is it all the same length? If they were trimmed for length were they de-burred?
I doubt if it's the Lee Factory Crimp die, as it just squeezes.
I would suspect that the shavings occur earlier in the operation, probably when the case is deprimed or the mouth expanded.
Any burrs on the expanding ball?

[Mauser48]

I have been getting this same thing on my .38's with a roll crimp and rcbs dies. They are at uniform length. I just pull it off with my fingers and they shoot fine and the brass is ok after.

[Walkingwolf]

Try using a a deburring tool before sizing.

[NSB]

Champfer and deburr after sizing and it won't happen.

[runfiverun]

I see what looks like a scuff ring on the boolit right above where the brass is roughed up.

[williamwaco]

The only time i have ever experienced that is when i trim and don't deburr.

I used to think the sizer would debur the outside and the expander would debur the inside.

Didn't work.

[Scharfschuetze]

I'm with the guys suggesting that you deburr your cases inside and out. I have experienced your issue in the past, but after religiously deburring all cases after trimming or new cases before using them the problem disappeared.

It should be a quick experiment if you have time today to try it. Let us know the results.

[Mauser48]

I will try this too and we can compare results.

[mongoose33]

I see what looks like a scuff ring on the boolit right above where the brass is roughed up.

I'm going to try some things this afternoon, see if I can get any of the above ideas to show fruit.

BTW, good eye on the "scuff ring," but it's actually not. It's this die from Accurate:

http://www.accuratemolds.com/bullet_detail.php?bullet=35-125E-D.png

It has a nose step for a slightl tight throat. So that's not it. :(

Just to add a few bits about how I'm doing this:

I may try a little chamfering and deburring to see what happens, but I've loaded 10's of thousands of rounds on this press, using a variety of taper crimp dies, and never had this happen.

I am using a universal casemouth expander that fits on the bottom of the case-activated powder measure. It's not perfectly smooth any more, but I've used it to create sized, primed, and casemouth expanded cases for working up different loads. I don't note any brass shavings on the cases when I do that.

I *do* have a spare of that CME, so I think I'll swap that out and see if it makes a difference. It is working on the inside of the case, so I don't see how it would be responsible for brass shavings, but you never know.

I also wonder if the brass is either brittle and thus the act of forcing the taper crimp back to parallel is breaking off the edge, or if somehow the crimp dies themselves are simply too rough or worn. I've run a q-tip inside the Redding to clean it, and I don't feel any roughness. It's almost as if the taper crimp is snapping off the outside edge of the case.

I'll add another post or posts as I learn more. This is just driving me nuts.

[Love Life]

It's a shave, not a snap.

[mongoose33]

OK. I think I have a decent idea what's going on. Before I say what it is, I'd just like to thank everyone above for their thoughts and ideas--I don't know which one put me on to what I think is the solution, but it may have been all of them.

Recall above the boolits are sized to .357, and that I haven't had this issue before. First time. Finally dawned on me that this is the first time I've tried to run this particular boolit, at this particular size, through my progressive and ultimately through the crimp dies.

On a whim, I took some of the .357 boolits and sized them down a bit further, to .356.

Guess what? Problem goes away. There's still a little bit of brass shavings, but nothing like what it was, and what there is is consistent with what I've always experienced.

I dug out some of my Missouri Bullet Company cast bullets, which were what got me started shooting cast bullets. Sure enough, they are sized to .356, not to .357.

I theorize that the slightly larger diameter puts more pressure on the case when it's in the crimp die, which is knocking off brass from the casemouth and resulting in all those brass shavings.

To double check, after running about 30 of the boolits through sized to .356, I pulled the Lee FCD, cleaned it to be sure there were no shavings there, then ran through 35 boolits sized at .357. Sure enough, the shavings came back. I pulled the FCD die again, cleaned out the shavings, and then ran another 50 through with boolits sized at .356. Almost no shavings.


So, again, thank you all for your willingness to help; the answer appears to be a boolit that's simply sized too large.

[44man]

Boolits do not peel brass and what does your gun like? .356" or .357"? What if it needs .358"?
Your problem is die related.
Even if you don't flare the mouth, you will get lead, not brass.
It looks to me like the coating, not brass.
On the partial seated boolit, I see no flare.

[Scharfschuetze]

Mongoose,

I've been sizing my 9mm projectiles to .358 for a while now. To help in the seating step/process I ordered a custom made expander for my Dillon press that measures .355." Such an expander, either .355 or .356 might help you in getting rid of your issues with the .358" boolits. The factory expanders for the 9mm usually go about .352-.353" or so. They are designed for jacketed bullets of .356" and thus seating a .358" diameter lead boolit is something of a stretch for the factory expanders.

[mongoose33]

Boolits do not peel brass and what does your gun like? .356" or .357"? What if it needs .358"?
Your problem is die related.
Even if you don't flare the mouth, you will get lead, not brass.
It looks to me like the coating, not brass.
On the partial seated boolit, I see no flare.

It's die-related but not die's fault--it's that the boolit is too large in diameter to work well in the dies. Remember that I had the same problem using either the FCD or the Redding taper crimp die. It's partly what led me to conclude it wasn't the dies that were causing it, because there's nothing to go wrong on the Redding--it's just a tapered and polished cylinder.

It's not the boolit peeling the brass, it's coming from the crimp die. That's why I showed the two stages on the press, prior to and after seating the boolit. There's not a lot of flare there, but there's enough.

I was a little slow on the uptake, but it finally dawned on me that the only thing that had changed from the previous production runs producing thousands of rounds was the diameter of the boolit. You wouldn't think that an additional .001 in diameter would make that much difference, but it surely does, at least in this case.

Reduce the boolit diameter, problem disappears.




Mongoose,

I've been sizing my 9mm projectiles to .358 for a while now. To help in the seating step/process I ordered a custom made expander for my Dillon press that measures .355." Such an expander, either .355 or .356 might help you in getting rid of your issues with the .358" boolits. The factory expanders for the 9mm usually go about .352-.353" or so. They are designed for jacketed bullets of .356" and thus seating a .358" diameter lead boolit is something of a stretch for the factory expanders.

Do you run them through a crimp die? That's the place where the problem occurs.

It's not the expander that's the issue--I'm using a universal PTX on my case-activated powder measure. You don't need a different PTX for every caliber, you simply raise or lower the CAPM in the press, and it expands the casemouth.

This is what it is: http://www.powderfunnels.com/products.html

It allows me to free up a station in the press for the RCBS lockout die, which checks powder level and locks up the press if the powder level is a squib charge or a double-charge.

******************************

I was out to the range this morning with rounds using the newly-sized boolits at .356, and they were...well, perfect, or as perfect as my ability will allow. Makes my day--I've been trying to settle on a production round and this is, finally, it.

Time to repair to the reloading room to add to the supply. :)

[Scharfschuetze]

Do you run them through a crimp die? That's the place where the problem occurs.

Yes, I crimp them with a Dillon taper crimp die at the fourth station on my 550 press.


I'm using a universal PTX on my case-activated powder measure

I'm not familiar with this PTX unit, but it does not look like it expands the interior diameter (ID) of the case. It looks like it only flares the case mouth.

As noted in my previous post, with your .358" boolit diameter, you'll probably want to expand your ID to at least .354-.358."

Below is an example of an expander that also increases the inside diameter of your case in proportion to your .358" boolit. You can see the difference between it and your unit. This one is for a Dillon powder measure and it expands the ID to .354" for the .358" diameter boolit. Looking at the photos for the PTX unit, it's not doing that and thus the tight fitting case may be squeezing down the diameter of your boolit to something less than your intended diameter. It may or may not and if it is shooting well for you then there's no need to worry about it.

As you are now sizing to .356" and the problem is gone the issue is probably moot at this point.

For info, measure the ID of your case below the bell after sizing and running through the PTX unit and let us know.

[Motor]

I'm surprised your loads worked well. You say there is a little boolit swaging using the FCD.

Just a little boolit swaging means you are sizing your boolits down within the case. If this occurs you are severely effecting your neck tension. The brass springs back the boolits don't. In a chamber on case mouth semiautomatic neck tension is really the only thing holding the boolits. The so called crimp is nothing but a mouth flair removal.

Your shavings are from the mouth edge of the case. They are swaged off of the case by the die. Try using your Redding taper crimp with the .357" boolits but back it off and slowly adjust it down in steps just until the case mouth flair is gone. Then see if the shaving is as bad as before.

I don't use my FCD on my 9mm cast boolits. I like mine .358" :)

Motor

[mongoose33]

I'm surprised your loads worked well. You say there is a little boolit swaging using the FCD.

Yes, there is, but it's not more than what I'm getting with the .356 sizing. The proof is in the pudding: they perform well--very well, in fact--so what swaging there is isn't extreme. The boolit is composed of alloy at about 12-13 BHN, so it's obviously obturating correctly. Velocity is also consistent with what I'd expect of a bullet of that weight and with the charge I'm using.




Your shavings are from the mouth edge of the case. They are swaged off of the case by the die. Try using your Redding taper crimp with the .357" boolits but back it off and slowly adjust it down in steps just until the case mouth flair is gone. Then see if the shaving is as bad as before.

I don't use my FCD on my 9mm cast boolits. I like mine .358" :)

Motor

I tried adjusting the Redding from too much flare on the casemouth to just enough to chamber; didn't make any difference in the brass shavings. And I always take it down a bit more--I shoot these in speed disciplines and thus the round must chamber and work well, so being "barely there" is not comfortable; there has to be a *little* wiggle room. :)

There was a clue in all this which just took me a while to figure out: I had the same problem with both the FCD and the Redding Taper Crimp Die. That suggested quite strongly that the problem wasn't in the dies, it was in something else--and that something else was the diameter of the boolit.