Leading with Lyman 40 S&W mold

[sig2009]

Gear,
Thanks for the suggestions. This is what I found so far. I fulled one of the loads that I was getting leading with. Not only did I have too much crimp but they miced at .398. Seeing the barrel was slugged at .399 that was a problem.

Second. I expanded the case mouth a little more to cut down on the swaging of the bullet going into the case. After creating another dummy round, belling, seating and then crimping I pulled that round and miced it. It miced at .400. I used Winchester cases. Miced case wall was .011. Bullet sized to .401=crimp .423.

I hope I am on the right track here. What do you think?

[geargnasher]

I'd say that should be fine, so clean the lead and copper fouling out of your barrel if you haven't done so already, load some up and go see what Mr. Pistol says about it, since his opinion is really the only one that matters here

Gear

[Gswain]

Gear always has had advice that worked out well for me, so thats a great starting point. I was having leading in my RIA 1911 for a while, and was trying to figure out why. Was eventually lead to the idea that the bore may not be as smooth as it needed to be. Got some lapping compound, went at it. No leading. I shoot .40 through my sig P226, with no leading. I water quench my boolits, and use recluse tumble lube twice. Size to .401, my bore slugs at .400. The AA#2 may be part of your problem, as it is a faster powder. FWIW, I have found 5.6 GR of AA#5 with a Lee 175TL boolit works great, now its the only thing I shoot out of it. Just finished up 700 or so of em. Good luck with it!

[HeavyMetal]

And there ya go!

Now that you've found the expander plug problem, case sizing bollits when seated, you should be able to get the leading gone with the load your using ( I still think you need to bump the load a touch).

AS Gear said really clean that barrel before you try another cast boolit load.

Keep us in the loop on how it goes!

[sig2009]

And there ya go!

Now that you've found the expander plug problem, case sizing bollits when seated, you should be able to get the leading gone with the load your using ( I still think you need to bump the load a touch).

AS Gear said really clean that barrel before you try another cast boolit load.

Keep us in the loop on how it goes!

I am going to bump up the load. As for the barrel it has a mirror finish now! I do plan to load some at 5.0 and some at 5.5gns and see what happends.

[sig2009]

Gear always has had advice that worked out well for me, so thats a great starting point. I was having leading in my RIA 1911 for a while, and was trying to figure out why. Was eventually lead to the idea that the bore may not be as smooth as it needed to be. Got some lapping compound, went at it. No leading. I shoot .40 through my sig P226, with no leading. I water quench my boolits, and use recluse tumble lube twice. Size to .401, my bore slugs at .400. The AA#2 may be part of your problem, as it is a faster powder. FWIW, I have found 5.6 GR of AA#5 with a Lee 175TL boolit works great, now its the only thing I shoot out of it. Just finished up 700 or so of em. Good luck with it!

AA#2 may or may not be part of the problem but this is a Lyman published accuracy load and they have been in the business for quite some time.

[462]

Keep in mind that Lyman accuracy loads are theoritical, not actual.

[geargnasher]

AA#2 may or may not be part of the problem but this is a Lyman published accuracy load and they have been in the business for quite some time.

Um, Yeah. Not an "accuracy" load anyway, they don't test accuracy anymore, only pressure. The "accuracy" loads merely show the lowest SD of the peak average chamber pressure for the components tested, in the pressure barrel/universal receiver. In the real world, as anyone here with a chronograph can tell you, the most accurate load for a gun has very little to do with good pressure or velocity numbers, and will differ greatly from gun to gun. Extreme long-range accuracy competitors will chase small SD numbers with pressure and velocity, but that isn't an end unto itself, only the group size and consistency is.

So, for your alloy, whatever it is, you might be served better by AA#5 if you prefer Accurate, or refer to my post above about MATCHING THE POWDER BURN RATE AND PRESSURE (CHARGE WEIGHT) TO THE ALLOY. It matters, especially with this caliber, that's why I took the time to explain it earlier. Finding the accuracy load that meets your satisfaction for barrel cleanliness and the gun's requirements for feeding is entirely up to you, and part of the fun!

Also, don't get caught up in the published COAL numbers, either. Every chamber and throat is different, just be careful of going UNDER the minimum number listed, this can drastically increase chamber pressure if you seat too deeply, especially with fast powders like AA#2. I tend to use the barrel as a gauge, seat until the case head is flush with the barrel hood and seat .010" or so deeper to allow for a bit of fouling. You may prefer a different way, I just thought I'd share what works for me in all my autos.

Gear

[sig2009]

Thanks Gear. Learning more and more every day. I do happen to have some AA#5and I'll give that a try. Also about OAL. I found that out when they said to load that specific bullet to 1.130 when in fact I had loaded it to 1.090 as this perticular LSWC should be.

[garym1a2]

Good information on this thread. A few days ago I brought a set of dies, molds and sizer to try for my glock22 in 40cal.

[geargnasher]

There have been three or four other excellent and lengthy threads on the subject within the last year or so, a brief search will yield a ton of good info.

Gear

[mpmarty]

Not to hijack the thread but does the advice given here also apply to 10mm?

Yes I've never had a leading problem with any of my five 10mm pistols but do adhere to what's been said here. Good advice for anyone trying to run with cast boolits.

My 45/70 (aka long distance axe) works like magic with cast boolits too.

[fredj338]

AA#2 may or may not be part of the problem but this is a Lyman published accuracy load and they have been in the business for quite some time.

Which means nothing. Every platform is an animal unto itself. IME, there is no such thing as most accurate across all guns. Just doesn't work that way.

I am going to bump up the load. As for the barrel it has a mirror finish now! I do plan to load some at 5.0 and some at 5.5gns and see what happends.

That is a HUGE jump up for such a fast powder. If you can't do it in 0.1-0.2gr increments, proceed w/ caution. The faster powders build pressure in a non linear fashion, meaning they go fine until you hit the upper pressure levels, then many will push the pressure curve vertical.

[sig2009]

Which means nothing. Every platform is an animal unto itself. IME, there is no such thing as most accurate across all guns. Just doesn't work that way.

That is a HUGE jump up for such a fast powder. If you can't do it in 0.1-0.2gr increments, proceed w/ caution. The faster powders build pressure in a non linear fashion, meaning they go fine until you hit the upper pressure levels, then many will push the pressure curve vertical.

Fred,
How is that a huge jump when the Accurate Arms starting load is 5.7 gn?

[Mavrick]

A tapered seating die is meant to "crimp" a j-word bullet, but when you are using a lead boolit, it's larger, not to mention softer. You should back the die out a bit so it doesn't squeeze the case/boolit quite so much.
When I'm loading my .40, or my 10mm, or any other straight auto case for that matter, I back the die out and insert the seating-spud deeper so that I don't crimp the case, but seat the boolit to it's proper depth. Then I back the spud completely, and screw the die in until I'm satisfied the bell has been taken from the case.
This is more or less the same as the old four-die loading technique. I'ne had no propblems since I started doing it this way.
Have fun,
Gene

[geargnasher]

Fred,
How is that a huge jump when the Accurate Arms starting load is 5.7 gn?

FredJ's point about taking it easy with charge increments of fast powders is still valid, and you ARE seating deeper than the load for which that data was tested if I read that right. .5 grain at 5.0 grains is a 10% increase. That's pretty drastic, regardless of the "level" of the load.

Gear

[NuJudge]

Fit is important, but I find hardness to be helpful. Some people use soft bullets and fast powders, hoping that the powder gas pressure will cause the bullet to bump up to the groove diameter, if it is larger than the bullet.

I am a believer in having a big and hard bullet to start with, especially in high pressure cartridges like the .40 S&W.

[cbr]

I haven't been around here much lately, but Geargnashers post on here was one of the most informative posts I think I have ever read. I printed it to keep with my loading data!

[sig2009]

I'd say that should be fine, so clean the lead and copper fouling out of your barrel if you haven't done so already, load some up and go see what Mr. Pistol says about it, since his opinion is really the only one that matters here

Gear

Well Gear,
I loaded some up and took to the range. Unfortunitely the problem still exists. After shooting about 20 from 2 different guns I still have the leading although about 50% less than before and it was much easier to clean out than previously. Where do I go from here? Lighter load,stiffer load,change powders. I checked the primers and there was no excessive pressure signs. I really would like to get this right. Thanks.

[geargnasher]

Loaded up some of what?

If you have leading, you have a poor dynamic fit and/or lube failure. Leading is caused either by gas leakage around the boolit (which cuts channels in the surface and deposits the dust ahead of the boolit in the bore where it is physically ironed-on the barrel's surface by the subsequent passage of the boolit), or by abrasion from copper fouling, bad bore surface, or from poor throat fit where the lube gets blown off of the boolit and out the bore before it even gets engraved. Another lube failure occurs with tumble lubes, where the pressures can exceed the lube's ability to do its job.

By "dynamic fit" I mean the fit of the boolit from the static fit in the case to muzzle exit, and it must fit and seal from the time the primer ignites all the way out. The boolit must fit the throat well enough to get a good, straight start up the pipe, and it must engrave without skidding the rifling and causing a trailing-edge leak (this is where slow powder and hard boolits can help), and it must travel the whole length of the barrel without losing the seal.

So, I'd say you still have boolits that are too small initially, are seated too deeply, are too soft for the powder speed, a lube that is failing, or some dimensional quirk with the barrel like no throat transition which can shave the boolit and leave it undersized from the chamber forward on its trip. Try a larger boolit and try using the chamber as a length gauge, making sure the boolit is seated out as far as it can and still function in the gun.

Gear