Casting Breakthrough with the 145-SWC. Effective on other moulds as well.

Smaller than expected bullet diameters of the 145 mould are affecting accuracy. Testing has shown that fullsized 360 bullets are best. 

The seam diameter ranges from .3591-.3594 in.  Across the seam typically ranges from .3584 to .3589. That is not good for achieving the best groups possible. 

First, the bottom line results.  The diameters now, after running a series of tests. measure .3598 to .3601 on the seam and .3593 to .3595 across the seam.  That's as dropped from the mould, before any aging grows or expands them.  (The effect of aging is the subject up an upcoming post.)

The final results are yet to be proven at the range, but that's coming soon.  So far the best groups have been 1.24 inches at 25 yards, with the undersized bullets.  From a rest of course, using my Red Dot Taurus 66, with a 6 inch barrel.

Lessons learned: Alloy temperature and mould temperature are absolutely critical. The alloy solution is easy, the Lee pot turned on full worked the best.  This is much hotter than most folks recommend, much.  Preheating the mould to 360 degrees also is critical.  The first cast will drop good bullets, then you must keep it from getting too hot.

First some data, then the process.  

The Lee pot is numbered 1 through 9, going all the way to what I'll call 9.5.  Casting at the different numbers, using the same one cavity and casting back to back, the diameters are in the chart. (click on it for a bigger view)

The numbers on the bottom are number of bullets cast in each test.  With more test bullets as the diameters increase.

The green line is the pot set to full hot, it's also is the one with the mould at 360 degrees.  This gives the maximum size, until the mould is too hot.  At that point size decreases, as you can see in the graph.

I ran a quick test and found that holding the mould on a wet rag for 5 seconds, than pausing for a couple of seconds, drops the temp 15-20 degrees.

Taking the lessons learned and putting together a test session produces the great results detailed above.  As a matter of fact a full casting session produced bullets even bigger.  All the way to .3601.  That's amazing.

The process that produces these fully sized bullets is repeatable and works on other moulds too.

The steps to follow are:

1. Get the alloy fully up to temperature before starting to cast.  Set to 9.5 then don't start casting until the pot cycles off.  This takes much more time than usual
2. Use a hotplate to get the mould to 360.  Use a basic kitchen thermometer with a flat bottom and stick it  into a middle cavity.
3. If needed, use the alloy in the pot to add heat to the mould if needed, dip the mould into the hot alloy.  Use a damp rag to cool it if it's too hot.
4. Start casting, (note: if one or two cavities vary in size, don't cast them.  Use the 3 or 4 most consistent and largest cavities. More on that in a future post as well.)
5. For the first third of the pot, every three casts cool the mould by pressing it onto the damp rag for a 5 count, remove it from the rag and wait another 2 count
6. Resume casting
7. The bullets look shiny when dropped and then show some marking as they cool.  Watch closely and you learn to tell from their "look" if the mould is too hot or too cool
8. After the first third pot it works best to cool the mould after 2 casts

That's it in a nutshell.  I suggest you do a similar set of tests and see how it works for you and your alloy.  Then refine the steps and the timing to work best for you.  

This test alloy is 98% lead and 2% solder, my preferred for all 357 magnum handgun bullets.

Next, the 145 bullets are aging for a week as part of another test.  The affects of the sizing/lube die, followed by the bullets enlarging will be documented in an upcoming post.  The range test is coming in the next few weeks.

Stay tuned and shoot well.

Update on 200 SWC, 145 SWC and also H110 Powder (most accurate loads update included)

The 360-200-SWC boolit has now proven itself with the best groups of any boolit so far.  With the ability to shoot between .5 and .6 inches from 25 yards it's incredibly accurate over 3.4 grains of 700X.  It's also a nice shooting light load.

The 360-145-SWC is hanging on the list with 1.2 inch groups.  This mould is a bit confounding.  However I've noticed that casting temperature and managing mould temperature is very critical.  I expect to post the results of alloy & mold temperature affects on boolit diameter, based on this mould.

The 200-SWC is a 2 cavity mould therefore casts boolits with a very consistent size.  The 358-429 is a outstaning 5 cavity, with 1-2 cavities that vary just a bit but has produced .6 inch groups.  The 145-SWC is dropping the smallest diameter boolits, at least most of the time.  When striving for the best accuracy, moulds with 2-3-4 cavities are more consistent and much easier to work with than moulds with 4, 5 or 6 cavities.  Casting with the 3 or 4 most consistent cavities promises to provide the tightest groups, more on that in the future.  The trade-off is throughput and how long it takes to cast 500 or 1,000 bullets. The best case is 4 or 5 cavities that cast equally.  When shooting groups less than 1 inch, and trying to break the .5 inch barrier, it requires extreme precision.

Magnum powders are now moving up the accuracy list.  The Lyman Cast Bullet Handbook got the load for the 358-429 right.  11.8 grains of H110 under the soft 6 BHN lead produced 1 inch groups with no hint of leading.

Below is an update to the top accurate loads.  The velocity isn't from a chronograph, but based on the recipes.

Rank	Mould	Weight	Group	Charge	OAL	Velocity
1	360-200-SWC	200	0.57	3.4, 700X	Groove	660
2	358-429	168	0.58	4.7, HP-38	1.620	900
2	358-429	168	0.58	5.1, 700X	1.620	1,200
3	158-SWC TL	158	0.61	3.5 HP-38	1.600	810
4	358-429	168	1.00	11.8, H110	1.620	1,260
5	158-SWC TL	158	1.10	5.1 HP-38	1.600	1,129
5	148-WC TL	148	1.10	3.5 HP-38	1.400	928
6	360-145-SWC	145	1.20	3.9 700X	Groove	1,020
7	358-429	168	1.30	10.3,2400	1.620	910
8	140-FN-LBT	140	1.40	5.8 700X	Groove	1,347

Update: 145 SWC Testing & 200 SWC Testing

I ran into a delay (besides the weather, which closed the range for days) due to a casting problem.  Based on early results I expected this boolit to be very accurate and group less than 1 inch.  As testing proceeded I could only get 1.2 inch groups.

Rather than blame the mould, I started reviewing the process, what may have changed and also started measuring the boolits more closely.  I discovered that for some reason they were slightly undersized.

The root cause: A new casting pot from Lee heats hotter than my old one.  This increase in alloy temp also heated the mould too much.  This is my fault for not double checking everything with a new bottom/pour furnace from Lee.

With alloy that was already hot, it heated the mould too much as well.  With the mould preheated on a hotplate, look at the graph of the boolit size as the mould is overheated (no frosting though).  As usual, click on the graph to see it full size:
 

The graphs shows the boolit diameter in sequence as 9 boolits were cast.  They start good and fall off as the heat builds.

Monitor the affect of alloy temperature and mould temperature on your diameters.  It has to be hot, but don't get to hot and end up with undersized boolits.  They just aren't as accurate.

The upside is that the only tests affected are the 145 SWC and early 200 SWC.  I have a great solution planned and once implemented and verified I’ll post it.  It's much more than just turning the pot down.  I want accuracy so it needs to be consistent.

Upcoming posts for additional accuracy tests:

• Results using H110 magnum powder will be coming in the next few weeks. 
• In the works is (already started for that matter) tracking the shrinkage of 357 boolits as they age.  When pursuing the best accuracy possible, it all makes a difference.  Especially for that event or day at the range when you want your “best of the best” loaded in the cylinder
• Oh, also coming is test results with a new-to-me Dan Wesson with a 6 inch and 2 inch barrel.  It has a different twist rate than the Taurus, more coming about that…  First I’ve gotta get all the lead out of the new revolver.  Enough has been removed to cast a 145 boolit, and there’s more!  My wonderful wife came to me on my birthday and said she’d like to buy me a gun.  Wow, I found the Dan Wesson and bought it.  After sitting at UPS for days due to icy roads it finally showed up at the Range/FFL.  It’s a Monson made model 15-2, what a nice trigger. 
• Ummm, there is that custom mould too.  Those results are a month or so out as the custom sizing die (for just $34) is needed as well.
• Did I mention my wonderful wife.  She puts up with all this and enjoy going to the range every so often too.  I really enjoy those range trips.

357 Magnum Accuracy Ladder, for Revolvers

Putting all the data gathered after a few thousand test boolits into a useful format is something I’m working on. First up is a list of diameters and alloys, starting with the most accurate. The bullets designs proven to be the most accurate all react to diameter and alloy changes very predictably.

357 Magnum Accuracy Ladder, base on results from tests at 25 yards off a rest.

Find the size and alloy hardness you are using and what will improve your boolit's accuracy.  Number 1 is the most accurate combination and number 6 has the biggest groups.  Other alloys and size combination's haven't proven to be nearly as accurate as this list:

1. 360 BHN 6 (pure lead with 1%-2% solder)
2. 359 BHN 6
3. 360 BHN 11 (WW or lead with antimony & tin)
4. 358 BHN 6
5. 359 BHN 11
6. 358 BHN 11

One point to clarify from earlier posts:  I referred to the alloy tested as 7-8 BHN, the Lee test kit doesn’t go lower than 8.  Then I was pointed to a very helpful chart that puts it at 6.2 BHN (thanks kelbro).  So all the other Blog posts are really talking about 6.2 as well, please make the adjustment when you read them.

While there is overlap that is not evident from the list, it still holds true at the range.

• That means there may be a few #2 groups that are better than a few #1 groups. 
• However the best #1 groups are always better than the best #2,
• and most of the #1 groups are better than most of the #2. 

Hope that makes sense.  Good shooting.

Quick and short update on the 145 SWC (full results to be posted soon)

A few folks contacted me and asked for any info that I may have for this mould.  They received their NOE moulds and want to get started.  So here is a quick update:

Assuming you read the rest of the blog and know that for highly accurate results soft and fat bullets (large anyway) work best.  The mould is dropping 99% lead with 1% tin at .3585 to .3595.  Pretty good as they are designed to drop WW at .360.  If possible go with an alloy as close to 98-99% lead with the rest some solder or tin.  If you all you have is WW, use that.  They both shoot some good groups, but the softer alloy produces slightly tighter groups off a rest, about 75% of the time. Softer is still more accurate.

The boolit seems sensitive to crimp, so a light to medium works.  If accuracy becomes a bit random you might be lose or tight.

Crimp in the groove and use either3.9 grains of 700X or 2.7 grains of 700X.  They are two very different loads and both standard pressure 38 Special loads.  4.0 would be the max for standard pressure. 

Let me know how this works out.  Hearing results off a rest or off-hand is always good.  Knowing a bit about your revolver is very helpful too.

I tested in a 357 using 357 brass, but these 38 special loads are the best so far.  I'll post more results to the blog as soon as I get final testing done

I'm also starting the same process with the 200-SWC so I'll post that too.

Note: I currently use a Lubrisizer with a .360 die.  Most of the time it doesn't do anything to the boolit except lube it.  If you pan-lube or tumble-lube try loading and shooting without sizing.  If they don't cause any problems like jamming the cylinder or making it rough to cock the hammer you are good  If they do then size to .360 and you'll be good.

Shooting Cast Bullets Over 1,000 FPS in a 357

Recently I've come across a lot of advice against shooting over 1,000FPS.  One even suggested that leading would quickly build and cause serious safety problems.  Another claimed that cast lead bullets melt at 1,200FPS.  Of course these claims are all false.  Two current Most Accurate Loads are rated (no chrono handy) at 1,120FPS and 1,200FPS.  Neither have leaded the barrel at all.

Another cast bullet myth is that loads over 1,000FPS require hard cast lead.  This is commonly accepted by many, if not most caster-handloaders.  The same two favorite loads are most accurate with very soft lead boolits. 7-8BHN, which is very soft.  In truth I can't measure the hardness of lead this soft as the Lee Hardness Tester starts at 8BHN.  The alloy is 10lbs of pure lead with 1 ounce of solder for tin, to help mould fillout while casting.  This is very soft, and it works very well over 1,000FPS.  Leaving a clean shiny barrel after 200 rounds or more in one session at the range.

With a good bullet design, like many SWC's, that fit the cylinder & throat, 1,300FPS and more, can and does work well.  That's with soft lead, not water dropped wheel weights or boolits hardened with any other method.

Some quick tips to shoot faster than 1,000FPS with lead:

1. Use a SWC from 158 to 200 grains
2. Avoid hard cast
3. Softer works better, BHN 8 is better than BHN 11-12
4. Bigger diameter is better, .359 is good, .360 is best (as long as your gun will chamber it)
5. Swaged or undersized bullets may work just fine, but may need a coat of Lee Liquid Alox to help lube them

The most accurate bullets bullets work the best at all velocities, especially over 1,000FPS.  Look at the info at 357 Magnum Accuracy is About Semi-Wadcutters

Check out the other posts about alloys and accuracy in a 357 magnum.  Note I can't stress enough that the softer lead is more accurate more often than harder alloys.  While it's very possible to get good groups with WW and even water dropped WW.  They do have more flyers.  The soft boolits will out-shoot the harder 7-8 times out of 10.

So don't worry about the 1,000FPS being a limit for your plain base boolits.  Bevel base can work, HBWC's are another matter, light loads only.

Off topic and just for fun, here is a picture of what promises to be a great 357 revolver.  Dan Wesson of CZ USA is releasing a new 715 this year.  Is that sweet or what!

The Most Accurate Boolits and Loads for 2010 (a best of .6 Inches at 25 Yards)

All testing was done in a Taurus 66SS6 for 2010.  That's a 6 inch 357 magnum revolver with at 16.5 inch twist rate.  The objective is to find the most accurate boolit (cast bullet) handload's at 25 yards.  Why?  Because it's fun to shoot great groups.  Using a rest is a way to remove the shooter from the equation and to better evaluate the boolits/load/gun performance.  A superbly accurate handload does translate to great  off-hand groups too.  It just takes range time and a lot of casting, handloading and shooting, which is the most fun of all when pursuing accuracy.

It's worth a reminder, there are plenty of boolits that are accurate up to 15 yards.  When moving out to the range maximum of 25, most of them didn't even group at all.  While groups (center to center) of 2 inches or less are good, I'm looking for 1.5 inches to make the list and better than 1 inch to keep the mould.

It helps with cash flow to sell moulds to buy more to test.  It's a money losing proposition, but it is a lot of fun.  And that's what this is really about.  Casting, handloading and shooting for fun.

I'm currently testing a 358-145-SWC that looks very promising.  However accuracy testing isn't complete yet.  I'll add more on that in the future.

The most accurate alloy in all testing continues to be very soft 7-8BHN.  I use pure lead with 1 to 2 oz of solder.  If anything, the alloy is softer and not any harder.  The most accurate size is 360.  There are actually 6 loads listed as there is a dead tie

1. 358-429, 168 grain Keith. OAL of 1.620 loaded over 5.1 grains of 700X or 4.9 grains of HP-38. Both loads have a best group of .6 inch with the 700X being more consistent. My mould is from NOE and is a joy to cast with.
2. 358-158-SWC TL, from Lee. OAL of 1.60 loaded over 3.5 grains of HP-38. This is a great deal and is a tumble lube design from Lee. Crimping into the second groove works best in the Taurus. This mould can produce a bunch of boolits fast, assuming a 6-cavity is used. The best groups are slightly bigger but still less than 1 inch.
3. The same 358-158-SWC TL from Lee over 5.1 grains of HP-38 groups just a bit bigger, but not much.
4. The 358-148-WC TL from Lee also grouped at 1 inch. OAL of 1.40 over 3.5 grains of HP-38 is an awesome wadcutter load and can group right at 1 to 1.25 inches on a good day.
5. 358-429, the 168 grain Keith, OAL at 1.620 loaded over 10.3 grains of 2400 can group at less than 1.5 inches.  It is the first magnum powder tested to be this accurate. It isn't a high-power load, but is the best grouping with this powder.
6. 140-FN-LBT, from Lead Bullet Technologies. Crimped into the groove and loaded over 5.8 grains of 700X grouped just under 1.5 inches. This is a near max load and the most accurate for this mould.

That is the top list for 2010.  These exact recipes may not be the best in your 357 revolver, however they should get you close.  It takes a bunch of patience and testing to fully develop the most accurate handloads for your 357 magnum, it's worth the effort.  I hope this can help you get there a little more quickly.  Just saving time and not wasting it on trying to alloy and pressure match should be a big help (see previous posts listed on the right).

In 2011 the refinement and testing will continue.  There are more moulds on the way and maybe a surprise or two in the works as well.  This Most Accurate list will evolve over time.  Let me add, the early 358-145-SWC results will upset this list once testing is completed.

Just for the record.  I'm not out to prove some theory is right or the best, or to disprove practices such as "alloy and pressure matching for accuracy".  I cast, load, test, measure, record results and then do it over and over.  The analysis of the results takes a lot of time.  I'm always force ranking the best results to the top of the list.  In the end the results speak for themselves.  If a "commonly accepted" practice doesn't work, I'll say so.  If it does work, I'll also say so.

Gotta prep for more casting in the morning so time is short.  These 145-SWC's are working out very well.  Stay tuned for more info.  Shoot well and be safe.