Shiloh Rifle Forums

.45-70 brass, I have a thumbler tumbler and when tumbling the mouth of the case gets peened, not a lot but enough that inserting PP bullets is affected. The preening causes the ID of the case mouth edge to be smaller than the actual case mouth. After a slight ID chamfer, the case mouth edge has very little material so it is easy to be deformed when tumbling. I have no idea if using a vibrating cleaner would alleviate this problem.
Thanks Richard

It might stop the peening but I don't think it will get your cases as clean. I straighten and very slightly bell the case mouth after cleaning and annealing. It seems to solve those issues.

Bryan

Most of the peening comes from pre rinsing the cases in a jug or coffee can when you shake it or when you just have a few in the tumbler.
Chamfering the case mouth to sharp will cause it also.

There us another thread here on how to fo it without peening, but i always got peened lips regardless of what i did, so i switched the the Charlie Young method.

Neither - ultrasonic'ed! No issues with peening, cleans well, needs less time.

Richard, if you load a liquid tumbler correctly ... zero peening
With ceramic media, 1/4 to 1/2 inch of media, tumbler filled half way with deprimed brass and burnishing solution covering the brass
I have never had any cases with peened mouths

My experience is similar to John Boy's. I barely cover the loaded tumbler with water. In the past I thought more water was better, but it didn't work that way. Now, minimize the water. My thumbler has the "high speed" motor setup.

Be careful how much you chamfer the case mouth. A thin case mouth edge just begs to be peened over.

Keep on hav'n fun!
MikeT

I forgot to mention that I’m tumbling dry with crushed walnut hull and my case mouths are pretty thin. I’ll try John Boys recommendation. Thanks Semtav, I’ll see if I can dig up Charlie Young’s method.
Cheers Guys

Well if you want purty cases, my way is not the answer. I scrub each case by hand with a test tube brush as they are soaking in a sink full of hot running water and dawn soap, put them in a coffee can full of cold water, rinse and dry on a rack. Before annealing each case is put thru a 3 stage hornady case tool. First stage is a nylon brush wrapped with 0000 steel wool. This polished the inside of the case, second step is a follow up with a nylon brush, just for the heck of it. 3rd step cleans the primer pocket. Ready to anneal and flare, prime, and load. Not for the fella that wants shiny looking brass as these are just plain ugly. Been using the same brass in my 45-90 LRE since 2006, no case stretching and have never had a separated case. Not for everyone, but works for me and a few others.

The following is from an article I wrote some time ago. The full article can be accessed at: http://www.texas-mac.com/Case_Cleaning_ ... _Pins.html
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Due to extensive testing there’s no question that peening is definitely due to rotary tumbling. And the rate of peening is determined by several factors: brass softness, rotational speed of the tumbler, type of media, how full the tumbler is loaded, how long the dirty brass was soaked prior to tumbling and finally the tumbler run time. If someone tumbling brass with ceramic or stainless steel (SS) media does not believe peening is taking place than they have not measured the lip width close enough before and after removing the brass from the tumble. The slight rolled over edge may not be sufficient to cause a problem or shorten the cases appreciably, but one cannot tumble brass with ceramic or stainless media without some peening taking place.

Just to be clear on what causes the peening, it’s not due to the media hitting the case lips. It’s the result of the collisions between cases. I found that peening takes place with cases tumbled in plain water without any media, but the rate of peening is much less than with SS pins or ceramic media. A case full of SS pins weighs more than one filled with ceramic media and significantly more than one filled with just water. Therefore the collision forces are higher between cases full of SS pins, as is the resulting peening when compared to cleaning with ceramic media or no media.

Wayne

As Dan T. posted years ago, Thumbler's Tumbler can be purchased with one of two motors -- high 3000 rpm and low 1550 rpm. The low speed (1550 rpm) motor combined with filling to 3/4 with water mitigates peening.

After my de-capped cases arrive home during a soapy water ride I use a drill motor with a wire bore brush wrapped with 4 ought steel wool to clean the inside...there is a lot of black crud coming out of the case when it’s dropped back in the water.

I tumble, then vibrate....

matt

Is this the high or low speed version?
I have the low speed and have never had an issue with case damage.
Gary

Flatguide, I used to use a brass/copper...whatever they are on the inside of the cases also. Not with steel wool, just by themselves. I quit when I started noticing a cross hatch pattern like when we hone engine cylinders. I was concerned that the bullet may get drag on the case and cause stretching or worse. Although I never had any real issues. Probably with the 0000 steel wool, it may not be an issue for you.