Tumble Lube & Your 357 Magnum Revolver

Tumble lube works, and is a great way to lube your cast bullets.  If you are new to tumble lubing, the basic process is published in the Lee Instructions.  These directions are very good, short, to the point and cover the basic process.  The two favorite approaches below are based upon these steps.

Tumble lube works on standard lube groove bullets, as well as on tumble-lube-bullets.  Your should try these approaches to see how they work for you, and see which one your 357 revolver likes the most.

Here are three TL358-158-SWC bullets, one of the most accurate and best designed bullets that I've found.  The first is lubed with Lee Liquid Alox (LLA) mixed with mineral spirits, followed by a dusting of mica.  The middle bullet is a clean, sized bullet to act as a reference.  The third is lubed with Johnson Paste Wax:

Approach 1

• First:  Prepare the bullets with WD40, lightly spray a bunch of bullets spread on a paper towel, and then run them through the sizer (don't let them dry before sizing).  This avoids having to lube twice.  It takes time for them to dry, which can be avoided and isn't needed.  A penetrating oil/lube like WD40 isn't good for gunpowder, however the lube will coat it, and prevent any problems.
• Second:  Prepare the lube, mix your Alox with Mineral Spirits, 2/1.  This mix cuts the pure Alox or Xlox, making for a thin even application.  Unless too much lube is used, it dries nicely, with very little stickiness.
• Third:  Tumble lube per the Lee instructions, then spread on wax paper to dry.  Use a small fan to help the lubed bullets dry more quickly, if one is handy.
• Fourth:  Put the lubed bullets into another container, add a small (very small) amount of mica and swirl it around.  Just like lubing.

Your are ready to load and shoot.  While Label lubes offers a great alternative called Xlox:

The mica can be bought from Midway, and probably other online sites too:

Approach 2

Johnson Paste Wax is becoming my favorite lube, it's awesome.  However testing isn't complete, hot loads will be put through the paces soon.  For lighter loads, the jury is in, it can't be beat in my opinion.  It lubes great, is accurate, and less messy than traditional lube or liquid Alox.  

Update: JPW works great with tumble lube design bullets.  However it did fail to lube a 170 grain Keith bullet, resulting in leading.  Keep that in mind when lube your bullets.  I plan to shoot a lot more of it with light, very accurate loads.  For full house Keith bullets I will continue to Lubrisize with Darr lube.

• First:  Prepare the bullets with WD40, lightly spray a bunch of bullets spread on a paper towel, and run them through the sizer (don't let them dry).  This avoids having to lube twice, once before lubing.  It takes time for them to dry, which can be avoided.  A penetrating oil/lube like WD40 isn't good for gunpowder, however the lube will coat it, and prevent any problems.
• Second:  Put the bullets into a plastic bag or container and let is sit for 5 minutes in hot tap water. This will warm the lead and will help the wax coat evenly.  They should be slightly warm to the touch, not hot and not cool. 
• Third:  Scoop a small amount of the Johson's Paste Wax into a container of bullets.  For 200 bullets, try a dime size glob of wax.
• Fourth:  Tumble lube just like Approach 1, then spread on wax paper to dry.  Use a small fan to help the lubed bullets dry more quickly, if one is handy.

Your are ready to load and shoot.

In Conclusion:

There are many other approaches that work too.  However, these are the techniques I use most often these days and just may work well for you too.

One other very noteworthy approach was created by Recluse, a member of castboolits.gunloads.com.  He created a mix called 45/45/10 that is hugely popular.  It's 45% LLA, 45% reduced JPW and 10% mineral spirits. Search with Google and you'll be able to find it quickly.   The detailed instructions are excellent and are available at that forum.

Shoot well!

There is a follow on post at: http://357shooter.blogspot.com/2011/06/update-best-way-to-lube-best-cast.html

Notes: Lee TL358-158-SWC Lapped for Testing, 700X & Variation / Issues, RCBS 38-150SWC Mention

A Lee TL358-158-SWC 6 cavity mould arrived the other day.  After buying & selling many moulds, I wanted to revisit this fine design, looking to refine the tumble lube process. Wow, this new mould dropped very small bullets. The .357 to .358 bullets are not what I expect.

Time to lap another mould.  To get each cavity to over .360 took a little longer.  Lapping it slowly and taking measurements often, now it's dropping these fully sized bullets.  Oh, this mould is casting great at 800-850 degrees.  I think the tumble lube grooves fill out easier then the grooves on a 358-429 mould.  The lack of deep squared off Keith grooves makes a difference:

 

They now weigh in at 163 grains when using 98% lead and 2% solder.  This newly-lapped mould has improved accuracy compared to the unlapped-one used originally.  When enough testing is complete the charts will get updated.

Early results using 5.3 grains of Unique look promising.  If it proves to be consistently accurate it will get added to the most accurate chart.

Now, info on 700X:  After loading many pounds of this powder, it finally has/had accuracy issues.  Just recently, 2 different canisters proved to vary quite a bit.  More than bumping the charge up or down 2-3 tenths of a grain.  Powders can vary 10% and still be in tolerance, but if you run into unexpected results, it could a bigger variation of the powder than usual.  There was no safety problem or concern, however groups opened up to the point of being horrible and at any charge - inaccurate.

I still have a 3 cannisters and will verify the third unopened cannister in the next few weeks.  In the mean time, further test will be with HP-38, H110 and Unique.  The first 2 are proven accuracy producers.  Unique is now at the top of the accurate powder poll.  In the past, it shot well, but wasn't one of the best.  I added it to the mix to revisit and see how it does.

As always, the results based on caliper-measured-groups will determine if it really does deserve to be on the Most Accurate Bullet Moulds and Loads Table.

In closing this update: Recently tests using the RCBS 38-150-SWC have shown it's a good shooter.  But so far not consistent enough to make the list.  It may work well in your revolver, but until it proves itself in my Taurus 66 it gets "try it if you'd like" mention, off-list.

Lapping a Mould: What to do if your mould is dropping small bullets

We've all had a mould that dropped small bullets.  It's expensive to send it out for machining, and the manufacturer may fix it how you want, but in many cases is a hit or miss proposition.  

You can fix it with a few tools. Carefully follow these steps and you can improve the bullets that you cast and shoot.  This translates to tighter and more consistent group sizes at the range.

First, here are a few 358-429 Keith's cast with a lapped aluminum mould, they are already sized and lubed:

There's various ways to lap a mould.  This is one technique that works well and is proven. This 358-429 mould is aluminum with 5 cavities.  The number of cavities doesn't matter, however other materials take longer and are more difficult to lap. 

The process, step-by-step:

1) Get some nuts, for 357 I use 1/2 inch, one per cavity
2) Heat the mould to casting temp                             
3) Open the sprue plate and rest a nut over each cavity

 

4) Cast through each nut, overfilling by a little bit.  If it runs a bunch,that's OK (if not full enough the nut may spin on the lead)
5) Drop'em out as usual, and let it all cool
6) Lightly coat the bullet with compound (note below)

The bullets in the picture below have already been used to lap.

7) Put each bullet back into the cavity it came from (twist off the lead if it keeps a wrench or socket from fitting the nut)
8) Either with a wrench or with a electric drill/socket start slowly lapping, while applying pressure on the handles.  Use a c-clamp (if handy) to tighten down the cavity being lapped, adding pressure slowly.  Lap each cavity for 1 minute (longer if by hand) per lapping session, and vary the speed and reverse direction if possible.   Keep it slow and you'll be good

9) Clean it up and go-to step 1

That's the process.  Use the cast bullets to actually do the lapping, in the same cavity they were cast in.  Measure each newly cast nut-bullet at a couple of points, like on the seam and then across the seam. Lap each cavity enough times to get the size you want, or just to polish it.  I lapped mine 3 times with 600 grit compound and 1 time with Rubbing Compound.

The lapping compound can be something like Wheeler 600 grit, auto rubbing compound (used this for the final-lap or polishing as it is very fine) or even toothpaste for polishing only.  Valve compound works too.

Because I use a lubrisizer, I wanted to get the minimum measurement to .0004 over my final size.  So with a .360 size as the goal, the minimum I wanted is .3604. If you don't size your bullets, just stop when each cavity is at the right size.

Benefits of a lapped mould:

1. The bullets just fall out of a lapped mould.  
2. Sizing  & lubing is easier as lube doesn't shoot-the-gaps and flood the die.
3. The best result is having fully sized bullets and not only shooting smaller groups but shooting them more consistently too

Lapping a mould is messy, so between sessions wash the mould at a sink with Dawn or something similar.  For a 5 cavity mould it takes 15-20 minutes for 2 lapping sessions.  So it doesn't take long.  Go slow and keep the stress down.
 

Good shooting!