BP damages brass cases ?

I dont normaly load BP cartridges, just front stuffers and lots of smokeless cartridges.
A friend wants me to load up some BP cartridges for him, caliber 45-120-500.
He has dies and said the cases (RCBS headstamped) were last fired with BP 8-10 years ago.
The problem is the cases were never cleaned after firing, just put back in the plastic box and I've read they must be cleaned right away or the brass gets weak.
The cases dont 'look' bad at all.
I just de-primed them and they dont seem 'weak' or have any corrosion, just look tarnished and in need of a tumbling.

Can these cases be loaded safely ?

TIA
Cheers, YV

Black powder is not corrosive. It IS hydroscopic.

If you live in a damp climate, the black powder residue will attract and hold water. That, in turn, will corrode the case.

If they cases are not exposed to moisture, they may be unharmed by the years of neglect they've experienced.

To be safe, I'd tumble them with steel pins and inspect them before use.

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Originally Posted by August

Black powder is not corrosive. It IS hydroscopic.

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I think you mean hygroscopic.

YV - as suggested, I would de-prime the cases, then clean them by soaking them in hot, soapy water for an hour or so. Replace the water and repeat until you get most of the residue out. Then allow them to dry (I use an old cookie sheet and my oven set to it's lowest temp for about an hour), and clean them as you would any other cartridge - vibratory or tumbler. Then give them a good inspection.

I think you'll find they're probably OK, but throw out any suspected bad cases. Stains/discolorations are not necessarily indicators of problems.

If theres a scab of green or gray verdigris there are often near invisible pin holes that penetrate the case wall. I've seen this when trying to clean old milsurp cartridges and figure its the same with BP cartridges.

I think this comes from the "good old days". Mercuric primer compounds would eat brass cases and old balloon case heads had less brass in critical areas as well. Modern cases, modern primers, no bad corrosion...I would think you are good to go.

Quote:

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Originally Posted by darkroommike

I think this comes from the "good old days". Mercuric primer compounds would eat brass cases and old balloon case heads had less brass in critical areas as well. Modern cases, modern primers, no bad corrosion...I would think you are good to go.

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Mercuric primers had little embrittlement effect on the brass of the old BP cartridges. Black Powder fouling actually protected the brass from the mercury fumes and deposits.
Mercury embrittlement of cartridge cases only became a problem when smokeless powders first came along.
Corrosive salts also became more of a problem when smokeless powders came along, because the through washing out of BP fouling with lots of water and soap if handy also dissolved corrosive salts and washed them away. Nitro-powder solvents dissolved residues of smokeless powder and copper or cupro-nickel fouling but barely touched corrosive primer salts.

Years ago I made the mistake of using straight Balistol without water or a water rinse when cleaning my Colt Navy replica. After being out of state for several months I found that for the very first time since owning my first BP pistol the bore had gotten rusty in the corners of the grooves despite having been clean as a pin to all appearances.
I;ve gone back to cleaning with hot soapy water and a scalding hot water rinse, then a careful drying out while still hot, followed by liquid wrench.

I've loaded .32 S&W rounds with BP, the fired cases tend to turn red or ruddy brown after awhile. Polished brass trigger guards or frames also turn ruddy brown where BP fouling mixed with crisco has lain un noticed for even a few hours.

Not BP, but American Pioneer Powder will corrode cases for sure.

I pulled boolits from 45-70 cases that had been loaded with America Pioneeer powder few years back

The powder was a solid hard mass, when got powder out,inside of the cases were severely corroded from boolit seating area all the way down.

I poured the powder from one case onto cement and stuck a match to it thinking would burn fast like BP. What I got was it did not burn, but exploded with an instant blinding flash, a very loud whomp and hair singed almost to the elbow on that arm.

Shudder to think what the end result would have been if had fired in my original Ballard.

So no more of the subs for me loaded in cartridges.

The cases should be cleaned in a rotary type tumbler if possible with ceramic or steel media. You should also deprime them before cleaning.
There is one more step that has not been spoken of and it will make a lot of difference in how your brass last and how accurate your loads are. The brass should by all means be annealed before loading.
This step is not that hard and it will go a long ways into not only keeping your brass from splitting but will also give you a good chamber seal. That seal will allow all of the pressure to be behind the bullet and give you better down range results. Take Care David