Saturday, January 21, 2012

Update on the New - Custom Lee 358-429 & Bullet Fit Tips

Getting a new-to-me Taurus 669 at the same time as the new mould came in created a double learning curve.  It's what I love to do, but it takes some time to develop great loads.  Finally, here's more detail about my target load and some early results from a full magnum load.

This Lyman styled six cavity mould is cut to my specs and drops soft alloy bullets over .360 inches.  Just as I wanted.

The Taurus has a conventional groove diameter of .357.  It's throats are huge, at .3595 and .360.  It's a good thing that mould drops some fat bullets! 

Bullet Fit Tips 

The basic rule for shooting cast is for the throats to be bigger than groove diameter, whatever they actually measure is less important, in my opinion.  If the throats are equal to the groove, the gun can shoot good, but it's not ideal.   If the throats are smaller, it's a problem, the gun will lead, most of the time, and accuracy will be dissappointing.

If you have some dead soft lead (sinkers work well), here's a quick way to check your revolver dimensions are OK:
  1. Tap the sinker into the muzzle, no more than 1/8 inch
  2. Grab it with pliers and pull it out
  3. From the cylinder face, see if the "sized" portion of the sinker will fit into each throat
If it won't fit, the throats are undersized and tight.  This is not ideal and the throats may need to be reamed to fix the problem.  Assuming the sinker fits, your gun is good.

Here's how my bullets checked out, this becomes important later:
  1. Unsized a bullet will not push through the throats of the Taurus
  2. Sized to .360, with a Lee custom sizer, they push through with finger pressure, using a pencil
  3. If they drop through, they are to small.  My Lyman .360 trims them a little to much, they drop through and they lead.
I tried my favorite tumble lube recipes, including Johnson's Paste Wax and Alox, and nothing worked. More about lubing later with each recipe.

Note: If you want, you can slug your barrel and throats and measure the slugs with a micrometer, the basic rule to prevent leading is for bullets to be +.001 or +.002 over groove size.  I've found that helps avoid leading, however often isn't the most accurate.  Using the simple approach above works as well, in most cases.

3.5 Bullseye Target Load

The 3.5 grain Bullseye load is still tops for a light target load.  I was suprised to some degree when this bullet like to be loaded short.  In 357 revolvers the vast majority of great bullet/load combinations are with a long OAL.  Pushing the bullet as far into the throat as possible has become almost second nature.  Loading a 358-429 so the nose is .005 from the cylindar face has proven to be a good starting point, backing it down from there.  Typically a 358-429 has performed at it's best loaded 1.620-1.630, in my guns.  Cylinders lengths vary a bunch, so your revolver may like a different OAL.  In this case, it doesn't seem to matter.

I always try a few loads loaded short, or near the minimum length for the given recipe.  The Lyman Cast Bullet Handbook list 1.553 as the minimum.  This load really came alive at 1.560 with a light to medium crimp.  Very accurate, and a great load that anyone can shoot.  At least in a 6 inch revolver, it does smooth out the recoil.

This load shoots best with a pan-lubed & unsized bullet.  They are over throat size an do not even push through the throats.

So the target load likes a short OAL, an unsized fat bullet that is over throat size and a light crimp.  Another surprise to me is that 700X was outdone by Bullseye, as they say: It is what it is.

12.7 H110 Magnum Load

The long OAL 358-429's liked 13.5 grains of H110, loaded short this bullet and gun really like 12.7 grains, with a heavy crimp.  It's a nice, big load, that shoots to the same point of impact, time after time.  I admit that after shooting a while I have to work to avoid flinching.

This full-house load works the best, still loaded short with the same 1.560 OAL, but with a heavy crimp.  Pan-lubing and then sizing with the custom Lee nose-first .360 sizer proved to be the most accurate combination.  This load likes the bullet to push through the throats with finger pressure.  Use a pencil to test your bullet / throat fit.  I suggest trying throat size and over-throat size bullets to see what shoots best in your revolver.

In Conclusion

So far, this magnum load likes a short OAL, a Lee sized bullet (finger pressure to get it through the throats) and a heavy crimp.  What else?

  • An old trick: So just as I'm thinking this is as good as it gets.  I decided to lube both grooves in the bullet.  The lube groove, and the crimp groove.  Loaded short, it's fully covered by the brass, so why not.
  • Wow, this shoots even better.  So let me add a lubed crimp-groove to the list of what works for this bullet, in this revolver.
The Bullseye target load also likes the short OAL with an unsized bullet, pan-lubed in only the bottom lube groove and a light or medium crimp.  The medium crimp shoots cleaner and is just as accurate, it's perfect for the range.
There will be more pictures coming, so stay tuned as I continue to ring this combination out.  Have fun shooting those tight groups!

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