Carbon build up in .357 Magnum....

I bought this old Three Screw Blackhawk .357 about eight or nine years ago from an older gentleman who I believe used it in cowboy action shooting. It had the transfer bar modification when I bought it. I removed that, and installed a steel grip frame:



I have no idea how much he used the gun, but I've put less than 5,000 rounds through it since I've had it. Saturday I had it out to the range and could load a .357 Magnum round in only one chamber.

This morning (Monday) I reamed out the chambers. A steel wire brush wouldn't touch the stuff, so used a 5/16" diameter wooden dowel, slotted to hold a piece of emery cloth. Chucked this into my drill press and worked the chambers really good until a loaded .357 round dropped into, and out of, the chambers.

Looking back at my log book, I have put about 725 rounds of .38 Special through the gun of late.

Bob Wright

P.S. Ya'll: I fit the steel grip frame myself, then just used a cold blue on it, thinking more might be done later on this gun. As you can see, nothing yet has been done.

You can save yourself a lot of grief if you always load in .357 brass. Don't remember the load for certain, but I think it was 3.5 grains of Hodgdon Clays in .357 brass with a 158 grain cast bullet.... makes a real light "plinker" load with almost zero recoil.

Real carberator cleaner works real good for carbon (not the spray stuff).
Ya might have to find a mechanic shop that has some. Sometimes ya gotta let it soak a day or two.

Carefull with that powered sandpaper. :wink: .

DGW

DGW1949 said:

Carefull with that powered sandpaper. :wink: .

DGW

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Yep!

WAYNO.

I never use 38 brass in my .357s for that very reason. I just down load the charge in them if I want target grade loads.

Nice find & nice looking piece. Looks like the pic was taken before you replaced the alum grip frame.

desertrat said:

I never use 38 brass in my .357s for that very reason. I just down load the charge in them if I want target grade loads.

Nice find & nice looking piece. Looks like the pic was taken before you replaced the alum grip frame.

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No, Sir, that's steel. I bought a brand new one for an Old Army and did the fitting myself. Then, thinking it will be a project gun, I just blued it with cold blue. That's beginning to wear thin in places, awfully thin.

Bob Wright

If that carbon buildup does get away from you, you can make a cutter from some 357 brass. Snip or file some teeth in the case mouth. Tap in, tap out, rotate, repeat. Most of that hard crust will flake and chip out. Whatever's left will likely come out with solvent and a brush. Chore Girl helps too. Way better for your chambers than emery cloth.

Your 357 brass your having trouble with wouldn't be Starline would it? I only use 357 Mag never any 38 in my guns, and all my brass works well in my guns except for Starline it keeps getting stuck or fails to fit my cylinders, I have tried it in both plain brass and nickel same problem with both, I've had to take 1000 grit sand paper and do some sanding on some of my Starline case's to get them to fit in the guns, it's like they have some high spots on them I have to rub down a bit then they pop right in.

It's OK to spend 90 seconds to clean em after every range session, too.

Guy name Skeeter Skelton use to load 38 specials in his 357 loaded to OAL of 357. I have dome this and it will solve some of your problems. In his book he writes about killing small game using 158 cast bullet and a dose of powder would have to look it up.

i fire 100 38 special cases to every one 357 i fire in all my 357's. i have only had that issue in one chamber in one gun before... guess i am lucky.

do you clean your cylinders every time you shoot?

mike campbell said:

It's OK to spend 90 seconds to clean em after every range session, too.

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What he said

I like that one. It has style and grace.

I can`t believe someone has`nt mentioned flaring a 357 case & pushing it into the chamber .

Letting the cyl. soak over nite helps soften the crude ring also .

Have`nt shot any spc. brass in my 357s since I built up my brass stash.

Anyways the flap wheel method did sound a little extreme, but I bet the chambers are shiney now !!

My Hornady ultrasonic case cleaner does a pretty nice job on revolver cylinders too.

I have on more than one occasion chucked a .40 cal bore-brush into a hand drill and cleaned the chambers that way.

The crude ring if put there by 38 spc. then 357mag loads shot it just compacts it & makes it imprevios almost to brushes. It has to be mechanically removed.

I just cannot understand never cleaning the chambers, and allowing the "crud" ring to turn into a diamond.

I have shot warehouse quantities of .44 Special and .38 Special in magnum chambered revolvers, and I've never experienced a chamber that could not be cleaned by a few passes of a brush and some Hoppe's #9.

WAYNO.

6gun said:

Your 357 brass your having trouble with wouldn't be Starline would it? I only use 357 Mag never any 38 in my guns, and all my brass works well in my guns except for Starline it keeps getting stuck or fails to fit my cylinders, I have tried it in both plain brass and nickel same problem with both, I've had to take 1000 grit sand paper and do some sanding on some of my Starline case's to get them to fit in the guns, it's like they have some high spots on them I have to rub down a bit then they pop right in.

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I have the same problem with Starline brass in my GP100. I didn't experience this problem with a S&W 686 that I once owned.

I used to clean guns for a few extra bucks & I can tell ya some shooters in my neck of the woods have never heard of cleanin a firearm !!! Ya say Hoppee`s & they think your talkin `bout some kinda new bean or summtin!!! LOL

I once traded for a Colt King Cobra that had the WORST crude rings I ever saw !!

I asked the previous owner how many 357mags he`d ever shot , his reply "357s never fit in the holes & only shot 38s in it, ever" That`s when I figured out the flaring the case for a scraper trick !!