Shot My First Cast Bullets--Leading!!!

[G. Freeman]

Hello Guys,
I have finally shot 50 rounds of my first batch of cast bullets using LEE 255 gr mold for 45 colt. The bullets mic'd .452-.4525". A very small few were in the .451" range. Bullets were unsized. All of these bullets are out of round. Cylinder throats measure ~.4525 to .453". None of the case bullets push though the throats by finger pressure.

I have shot a lot of commercial cast bullets sized .452" in this revolver with no leading issue.

Alloy: coww
lube: lsstuff's xlox (1 coat applied very lightly), tumble lubed
load: 8.0 gr Unique
gun: S&W M-25

My first batch showed decent accuracy, but the barrel leading was significant--through entire length of bore with strips of lead embedded in the grooves.

Could you enlighten me on what may be going wrong?
1. not enough lube? since I lubed lightly?
2. out of round bullets causing blow by?
3. need a larger diameter bullet? .453 to .454"?

I would appreciate your input. Thanks in advance.

[BJK]

Here's my experience with bullets cast with LEE "no sizing needed" molds. Or that's what I assume the claim was for the mold, I was only told that they didn't require sizing and what little I knew back then told me that was just wrong. A friend cast a hundred or so for me in 9mm. So I lubed with Alox and loaded them up using my known load for that bullet weight. They were horrible. I didn't fire enough of them to have huge leading problems, the accuracy was enough to tell me to stop. I'm just a beginner in bullet casting so I can't help you directly, but I can state that I'll never put another unsized bullet through any firearm of mine. I'm also moving into powder coating to get the benefits that accrue from that.

Others with far more knowledge than I have will be by to help you I would imagine.

[guy_with_boolits]

I am a beginner and also had massive leading, I've learned many things, that could have to do with it:

MANY things could be crushing your boolit so its size when fired is smaller than it needs to be to prevent leading from gas erosion, such as:

-the case not being expanded enough (not flaring, EXPANSION)
-the lead could be too soft, allowing it to be crushed easier
-certain dies can crush it, like a LEE factory crimp die

Pull a boolit you've loaded from a loaded round and measure it so see how its doing. Measure the driving bands separately. The bottom one is most likely to be crushed since it would be doing the job of expanding the case.

[ryanmattes]

I'm fairly new to this too, but everything I've learned says .001-.002 larger than the bore diameter. That's a likely suspect for the leading.

I'd also try using a wax lube, the bullet design usually has the right size lube groove for the slug. If that works, then try alternative lubes.

I also load jacketed with 8gr of Unique, but found with cast 255gr my revolver likes more like 6.5gr. Ladder it down and see if that helps.

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[Bazoo]

Not enough lube, I use enough you can see it when dry.

Maybe a constriction at the threads. Have you slugged the bore and felt for a constriction? If the commercial you shot was soft, then it obturated to not lead. Could be the throats are undersize to the bore, and soft bullets obturated to mask that as well. COWWs won't obturate with that load, they are hard enough for gc'd rifle bullets at 30k psi.

[tomme boy]

The alox was the problem.

[mehavey]

The alox was the problem.

Properly applied/dried, "the alox" is never "the problem"

https://thefiringline.com/forums/sho...94&postcount=6

https://thefiringline.com/forums/sho...4&postcount=13

https://thefiringline.com/forums/sho...7&postcount=21

https://thefiringline.com/forums/sho...41&postcount=5

A. Can the OP tell us more about how the ALOX was applied -- and especially how/how long dried....
B. I do suspect (also) suspect undersizingin the mix

[Targa]

Maybe try fattening those bullets up to .453 by water quenching, dropping the temp your casting at or adding some antimony and tin...foundry type alloy from Rotometals is a good quick way to do that. Kind of a fine balance though, to hard of bullet at lower velocities could effect the barrel leading as well......the whole obturation thing like Bazoo mentioned.

[Castaway]

If you’re using a six cavity, it’s easy to not get the mould closed completely, causing out-of-round bullets. Check to see if any lead splatter is on the inside face of mould or in alignment pin/hole. Also, because the end cavity is so far away from the fulcrum, it’s also easy to not close the mould completely. Take time occasionally to close the empty mould with sprue plate open. If you see light, tweek your technique until no light shows through.
I’m also generous about the amount of Lee Liquid Alox I apply, going not for the golden sheen, but brown. I put mine in a plastic tub, apply alox and shake, let sit there a few hours and come back to shake again. Shake next morning and until dry and store for later use.
If after checking your technique and are convinced the mould’s out of round, contact Lee. It doesn’t happen that often, but it can

[USSR]

G. Freeman,

Since you are using a S&W Model 25, which are well known for having oversized cylinder throats, have you measured your cylinder throats? With one of my Model 25's, I have to use .455" cast bullets in it. This should be your first step in looking for the cause of your leading.

Don

[onelight]

You mention you have shot commercial cast that did not lead , have you measured those bullets to see what diameter they are ?
When you mentioned you tried the bullets in your cylinder throats you said "case bullets" not sure what you did , will a bullet out of a case drop through the cylinder throat ?
Alox will work if everything else is ok , as cast (no sizing ) will work if fit and everything else is ok . If you are using a carbide FCD it may size your bullet , remove all the case bell in the seating die if you feel the carbide ring bump over the bullet as the cartridge enters and exits the FCD that is a clue But if commercial cast worked with the same dies probably not the problem .My 45 acp FCD are tighter and are more likley post size . My 45 colt FCD dies don't post size any with .452 bullets.
You can slug your cylinder throats and barrel with pure lead , a round ball is what I use but some use pure lead sinkers . Or use pin gauges if you have them . If you have thread choke you will feel it when slugging the bore and the slug hits the portion with the choke the slug will measure the tightest place in the bore if driven all the way through.
In my experience it is usually a combination of things that cause leading . The previous posts show everyone's personal experience with eliminating it in a particular gun and load .
If you have shot commercial cast that did not lead you have bullets to compare to the ones that did lead to to get some ideas on what might work .

[Dusty Bannister]

One of the reasons it is desirable to size the cast bullets is that it will clearly show any out of round and undersized condition. The sizer either leaves the driving bands clearly sized by the die, or there is no indication of contact to the driving bands and that shows a gas leak will occur. Hot gasses passing around the bullet cut the bullet and deposit leading in the barrel ahead of the bullet.

The tumble lubes will prevent bullet leading, IF the bullet completely fills the bore. It will not prevent leading if the bullet is undersized at all. One light application is usually not sufficient, two is better, and completely dry before loading.

From the sound of your measurements, if done with a micrometer, your castings are undersized and you either need to lap the mold larger, or perhaps consider powder coating to enlarge the bullet diameter. This will also require sizing the bullet with a push through size die. With powder coating you will not need to worry about Lee Liquid Alox (LLA). A softer alloy is not going to be harmful, and might be better. The 8 Grains of Unique is a favorite load of some shooters of 45 Colt with 250 grain cast bullets.

We have to assume that the bullets are all well filled out and just on the verge of frosting so they are at full diameter. Shinny bullets with rounded band edges will always cast a bit undersized and that could also be part of your problem. What is the appearance of your cast bullets in detail please?

[Wayne Smith]

From what you posted - 1) out of round boolits, 2)slightly smaller than bore, 3)will not push through cylinder - but out of round so part of them will and part won't. If they are cast hard and not obdurating this is your problem - the boolit is out of round enough for gas cutting through where it's not contacting - thus leading. If they are soft they should bump up and fill the throat and bore.

In short your boolits are too small in one dimension and too hard to obdurate - thus leading.

[Larry Gibson]

Add 2% tin to the COWW.

Cast with the alloy at 710 - 725 degrees.

If a 6 cavity mould before pouring ensure the blocks are closed and do not hold the sprue plate handle, hold only the mould block handles.

Alox? What alox? If LLA then read the instructions, use a Lee push through sizer of .452 or .453 and lube again as per lee's instructions. Let the lube dry thoroughly between coats and before loading..

[dverna]

The good news is you know .452" commercial bullets do not lead. They will be harder than what you are casting with coww.

First thing I would do is sort bullets and cull any that are under .452 in any direction. Easy to do if you size...any that size with some force are going to be OK...those that do not need some force...discard. Push through sizers are cheap. Or you can get by by measuring 50 with a micrometer for the test. Load the .452+" bullets up and see if they lead. If they lead, your alloy may be too soft and bullets are sizing down when seated. Easy to check...pull a few and measure them after loading. Do the same measurement after pulling commercial bullets. If the cast bullets are sizing down, and the commercial bullets are not, your alloy is too soft.

If many of your bullets are undersize as cast, you can "beagle" your mold...do a search. Out of round is not a problem unless it causes one side of the bullet to be less than groove dia. You MUST be at groove or slightly over at every point in the bullet. Out of round may affect accuracy slightly but not leading.

BTW, commercial bullets are almost always produced with 92-2-6 (lead, tin, antimony) alloy. It is easily available (what I buy for casting) but your alloy can be doctored to replicate it.

[PositiveCaster]

Leading is caused by gas blowby around the bullet, so the bullet’s size as it goes through the barrel is important. Bullets which are too hard will lead more readily than soft bullets, especially with the OP’s low pressure load (likely around 750 fps) because they will not upset to fill the bore. Harder bullets will just make matters worse. All this has been demonstrated for decades by CBA members, by Dave Scoville (former editor of Handloader magazine) and by Veral Smith of LBT among many others. Nothing new here, yet so many choose to adhere to obsolete “theories” about cast bullet leading.

Many years ago (40+) I was loading for a NMBH in .45 LC using unsized Lee 255FN bullets cast of coww lubed with liquid alox. I was using a “ladder” technique starting at 8.0 grains of Unique and ending at 9.5 grains in 1/2 grain increments. I was firing into snow to capture the bullets. What did I find? Bullets fired with 8.0 and 8.5 grains had severe gas cutting on their bases, and there was plenty of lead in the bore. The 9.0 load had much less gas cutting, and the 9.5 load had no gas cutting at all - under pressure it had obturated to fit the bore perfectly. I learned a lot about cast bullets that day.

We know that the OP’s cylinder and bore dimensions are okay because commercial bullets don’t lead. Bottom line, it’s most likely that the OP’s only problem is using too hard an alloy, or too light of a load for that particular alloy.


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[dverna]

We know that the OP’s cylinder and bore dimensions are okay because commercial bullets don’t lead. Bottom line, it’s most likely that the OP’s only problem is using too hard an alloy, or too light of a load for that particular alloy.


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I thought commercial alloys were in the 15 BNH range and COWW at 10-12 BHN.

[matrixcs]

In my experience with leading out of round with min width less than bore dia will guarantee leading. I now size all blullets if out of round and most will round up. If your cast is too hard to round up then powdercoat to bring the size up and size again...
fyi: I have lapped most of my molds to give me casts large enough to size down to my preferred diameter.

[Larry Gibson]

8 gr of Unique under a 255 cast in the 45 Colt is ging to push 850 fps +/- ....not a "low pressure load (likely around 750 fps)".

Commercial bullets will be "harder" than the COWWs the OP is using. The Commercial bullets aren't leading with the same load because the lube is working.

The groove diameter on a S%W M25 45 Colt is going to be .451 +/-. Pushing a .451 - .4525 cast bullet into a .451 barrel will cause the bullet to swage down not "upset to fill the bore". Also if the cast bullet is lubed the bullet will swage down to less than .451 because it is riding on a layer of lube. The "obsolete Theory" here is the belief that a cast bullet the same as or larger than groove diameter will "upset to fill the bore". It will not, it will be swaged down. Some cast bullets can/will obturate (upset to fill the) the throat of the cylinder. If the throats are considerably larger than the groove diameter of the barrel then the swaging up in the cylinder throats and then swaging back down again in the barrel does nothing for the balance of the cast bullet and can very easily be more detrimental to accuracy.

The OPs leading problem are no doubt is partially caused by the COWWs used which probably have 2 + % antimony and little or no tin. Adding the 2% tin will balance the tin with the antimony creating the sub-metal SbSn which will mix into solution in the lead and give a better ternary ally. It will be a bit harder also but no where near as hard as most commercial cast bullets.

The major issue with leading is not always gas blow by but most often an inefficient lube that is not doing it's job or an insufficient amount of lube. The OP has not responded yet as to what "alox" he is using.

[mehavey]

My Tier-II New Vaquero 45 Colt loads are:

Both shoot inch and a half
Both leave mirror-finish bore on just a dry patch

Lesson 1: You can shoot amazingly soft bullets w/ thin-film LEE ALOX at relatively high pressures
Lesson 2: If you insist on hard(er) alloys, up the pressure or they'll go skittering down the bore
Lesson 3: Lee ALOX -- applied thinly/surface treatment and dried -- is magic stuff