Had leading trouble and could use some help (my first cast boolits)

[mcooper]

Hello everybody,

I've been at this forum for a while but just started finding time to load some boolits I have cast. I have a smith and wesson model 640 that I am loading .38special plinking loads for.

I'm using a lee 358-158-RF mold, a lee .358 sizer, and used lee alox for lube this time.
I was just shooting my first workup loads (a total of 11 shots) and I only used 3.7 grains of bullseye for my max load. I noticed a few lead streaks in the grooves of the barrel in the first 1/3 of the barrel that is closest to the cylinder. It took me forever to clean it out with a brush, and I'm afraid this is too much leading in my revolver.

I'd like some help trouble shooting...
I was wondering if the .358 sizer is too large of a diameter? I calipered my boolits and got .3585ish when using little force to close the caliper. Should I get a .357 or .356 sizer die?

I only let the alox dry a couple hours before I loaded these boolits. Also I'm willing to try the paste wax/mineral spirits/alox combination if that is better; I also have some beeswax and I hear it can be a good lube.

Do you have any other suggestions? I want to avoid the heavy leading I experienced this past range session.

Thankyou for your advice and have a merry Christmas!

[RobS]

Your boolit diameter is probably not too large as they can size down if they were once they go through the cylinder throats upon firing. The question is are the cylinder throats too small for your groove diameter. Did the boolits you cast and sized go through your cylinder throats? You should slug your barrel and then see if the slug will go through each of the cylinders as a minimum to seeing if your revolver has the makeup conducive to shooting cast.

As to the boolits after casting we need more info. Are these air cooled and what was your alloy. Did you cast them and then load within a few days? If your alox was straight and you didn't give any help with drying time such as with a fan etc. then I don't think they would have dried enough, but doesn't mean they couldn't have.

More info regards to alloy, age of boolits before reloading and having info regarding your gun's cylinder throat to barrel groove diameter will help a great deal.

[mcooper]

Your boolit diameter is probably not too large as they can size down if they were as they go through the cylinder throats upon firing. The question is are the cylinder throats too small for your groove diameter. Did the boolits you casted and sized go through your cylinder throats? You should slug your barrel and then see if they slug will go through each of the cylinders as a minimum.

As to the boolits after casting we need more info. Are these air cooled and what was your alloy. Did you cast them and then load within a few days? If your alox was straight and you didn't give any help with drying time such as with a fan etc. then I don't think they would have dried enough, but doesn't mean they couldn't have.

More info regards to alloy, age of boolits before reloading and having info regarding your gun's cylinder throat to barrel groove diameter will help a great deal.

Sorry, I meant to include my alloy info and forgot. I used clip on wheel weights and air cooled them. I cast them nearly a year ago.

[noylj]

For best accuracy in a revolver, the bullets must be a slip fit in the cylinder throats and at least 0.001" over groove diameter. In an ideal world, you throat diameters will be 0.358" and your groove diameter will be 0.357".
Have you verified that the bullets are a snug fit in the cylinder throats?
Have you slugged the barrel so you know the groove diameter?
In most cases, as I remember, leading at the beginning of the barrel indicates the bullet may be too small or the alloy too hard.
Someone will correct me quickly if I am wrong.

[mcooper]

For best accuracy in a revolver, the bullets must be a slip fit in the cylinder throats and at least 0.001" over groove diameter. In an ideal world, you throat diameters will be 0.358" and your groove diameter will be 0.357".
Have you verified that the bullets are a snug fit in the cylinder throats?
Have you slugged the barrel so you know the groove diameter?
In most cases, as I remember, leading at the beginning of the barrel indicates the bullet may be too small or the alloy too hard.
Someone will correct me quickly if I am wrong.

I have yet to slug anything as I have no soft lead balls... could I cast some soft lead boolits and drive them through?

ETA: The boolits freely slip through the cylinders with no resistance.

[RobS]

I would size them bigger then. In a revolver .001 can stretch to .002 and even .003. If you can put the bullet into the cylinder and it takes just a bit of push to have them exit that is about perfect. You could cast a some bullets and then as soon as they cool (I mean as soon as they cool to handle, maybe even warm) use them to slug with as they will be soft enough for all practical purposes. Also measure the slugs directly after and not a day later as WW alloy as the tendency to grow a bit as they age harden.

I would size them bigger then. In a revolver .001 can stretch to .002 and even .003 over groove diameter and I prefer to fill my cylinder throats for best accuracy. If you can put the boolit into the cylinder and it takes just a bit of push to have them exit that is about perfect IMO. You could cast some boolits and then as soon as they cool (I mean as soon as they cool to handle, maybe even warm) use them to slug with as they will be soft enough for all practical purposes. Also measure the slugs directly after and not a day later as WW alloy as the tendency to grow a bit as they age harden.

Your boolits are probably hard enough since they were cast a year ago to more than likely not swag down in the sized case upon seating, but pulling a one will verify wouldn't hurt.

[mcooper]

Thankyou all for the suggestions, I'll try slugging the barrel this weekend.

So what do you guys think was causing my leading?
Also is there any reason that this revolver may have trouble shooting cast boolits, or shooting them accurately? It will drive nails with jacketed bullets, I didn't accuracy check the cast boolits I made as I was just shooting the 11 workup loads I had.

[runfiverun]

lube again.
two light coats that are dry are better than one globbed on coat.

you definately want oversized.
did you clean all the copper from the bbl?
and sometimes just a powder change will do it.

[mcooper]

lube again.
two light coats that are dry are better than one globbed on coat.

you definately want oversized.
did you clean all the copper from the bbl?
and sometimes just a powder change will do it.

Just to be sure...I want bigger than .358" diameter? what if my barrel slugs at less?
I didn't clean all the copper before I shot the cast boolits from the revolver...but I think I did in removing the lead. I'll also use a copper solvent cleaner this weekend.


I guess I should get a cast boolit reloading guide....any recommendations?

[rbstern]

First of all, reduce the powder load by approximately 0.5 grains. 3.7 grains of Bullseye is a 38 special +P load when shooting that weight of lead boolit. No need to go there (yet).

Clean the barrel as thoroughly as you can so your next test starts as clean as possible. For the next batch of boolits, use a lot more lube. more than you think you need. It'll be smokey, and the revolver will get a bit messy from extra lube. But that's ok because when you find the right amount of lube, the cleanup will be much easier to deal with than scraping lead from the barrel.

If that works, you can start cutting down on the lube in the next batch until you find the sweet spot.

If that doesn't work, then you can start to look more closely at mismatched dimensions between bullets and bore, which is a more complicated issue to solve.

I suggest this approach because you are using one of the easiest-to-get-it-working-right combos...38 special and wheel weight boolits in a quality revolver.

Recommended book: http://www.midwayusa.com/viewproduct...tnumber=796528

[RobS]

If that doesn't work, then you can start to look more closely at mismatched dimensions between bullets and bore, which is a more complicated issue to solve.

Boolit fit is the most effective way to stop leading. Putting more lube on is only a Band-Aid and accuracy will be harder to find with a boolit that does not fit the gun right. That is proof in the pudding.

What are your boolits as cast diameter? If they are bigger and will chamber try them. You may not need to size them at all, just lube them.

As to if your barrel’s groove diameter being larger than your cylinder throat diameters then you'll have a tougher time getting cast boolits to work in your revolver. You'll have to rely on obturation of a soft bullet to fill the bore. The other option would be to have the cylinder throats reamed .001 over the groove diameter. I however don't believe your revolver is like this as your chamber throats already take a .3585 sized boolit and the barrel would really have to be out of spec. I'm not saying it can't happen though.

[mcooper]

Boolit fit is the most effective way to stop leading. Putting more lube on is only a Band-Aid and accuracy will be harder to find with a boolit that does not fit the gun right. That is proof in the pudding.

What are your boolits as cast diameter? If they are bigger and will chamber try them. You may not need to size them at all, just lube them.

As to if your barrel’s groove diameter being larger than your cylinder throat diameters then you'll have a tougher time getting cast boolits to work in your revolver. You'll have to rely on obturation of a soft bullet to fill the bore. The other option would be to have the cylinder throats reamed .001 over the groove diameter. I however don't believe your revolver is like this as your chamber throats already take a .3585 sized boolit and the barrel would really have to be out of spec. I'm not saying it can't happen though.

The sized boolits literally dropped through my cylinder throats, so I can go bigger and be fine there.

[runfiverun]

yep it's your cylinder throats you wanna fill not the bbl.
if yer leading is way down the bbl either your lube is giving out, or you need to try another [usually softer] alloy.
if yer in +p territory you are working in a narrow window with fast powders.

[RobS]

Good, then try some unsized, as cast. Make sure they are hard enough by the time you load them though. Aging of WW bullets takes about a week and a half to be hard enough for reloading.

[RobS]

runfiverun:

The leading is in the first 1/3rd of the barrel as stated in the original post.

[RobS]

mcopper: Which S&W 640 do you have; the 357 or the 38 special?

[EDK]

Don't forget that you can put some choreboy on a used bore brush and clean the lead out easily. Make sure it is the copper version rather than copper plated steel. I have occasional problems from a bunch of VAQUEROS that get a bit of lead right at the end of the forcing cone...probably due to problems caused when the barrels were installed...see threads on fire lapping.

[mcooper]

mcopper: Which S&W 640 do you have; the 357 or the 38 special?

I forgot that there are .38 640's. I have a 640-1 chambered in .357 magnum. I just wanted to start with .38 loads to cut my teeth on.

[RobS]

Are you using 38 special brass or 357?

[mcooper]

.38 special brass for these loads, but I have .357...just less of it.