Unique cause leading?

[Bazoo]

My Ruger SBH normally leads a little right at the start of the rifling. This with 9 grains unique I've been shooting.

So long story short I had tested some loads with IMR 4227 and I removed the cylinder and there was no leading. Then I shot a few cylinders full of the unique charged loads and checked and there was leading. There was no other change in the ammo. Is it a unique thing? Or maybe because the 4227 was at higher pressure it obturated and shot cleaner?

The particulars
44 magnum caliber
Hornady brass trimmed 2.255
RCBS 44-245-SWC WW+Sn sized .430
50/50 lube
CCI 300

The IMR4227 charged cartridges varied from 19.5-21.5 as I was testing. The unique was 9.0 grains. Everything else was identical.

Suggestions and ideas welcome.

[Martin Luber]

I think the 4227 would burn cooler and develop pressures more slowly than Unique. I had trouble above 8 grains in a 44 w/o a gc

[Bazoo]

Could it be where the pressure peaks?

[BigAlofPa.]

I load all my 44 mag with unique. I never had leading with it. I have a SBH. I load from 8-12 grains depending on how much power i want. I use the hi-tec coated 18 bhn. Now with my SW 25-5. I leaded up no matter the charge or powder with BHN 18. I had to order BHN 12 for it. The leading cleared up. Hope you get it figured out Bozoo.

[Bazoo]

Preciate the replies. I reckon if it was easy anyone would do it.

[Three44s]

Preciate the replies. I reckon if it was easy anyone would do it.

At your 9 gr level, Unique should not be spiking your cast towards leading. I do the Skelton load of 8.5 gr. (only slightly lower and it’s a gem). My closest next power level above that involves HS6 and just a hair below 12 gr (11.8) and that gives me more power and still no leading pressure around 24,000 cup as I recall.

As HS6 is slower it gives me a slower dwell time. Your 4227 load would be even softer on the launch than that.

It seems to me that your problem lay elsewhere than your powder and charge choices.

Best regards

Three44s

[Bazoo]

Next I'm going to try ww bullets sized .431. Then if that still leads with unique, I'm going to try 50/50 alloy. Course I could just shoot GC bullets but that ain't no fun.

[ABJ]

Next I'm going to try ww bullets sized .431. Then if that still leads with unique, I'm going to try 50/50 alloy. Course I could just shoot GC bullets but that ain't no fun.

I think you hit the nail on the head here. My redhawk has .432 cylinders. If I use .430 boolits and unique I get leading until I get up to 9 grains then its fine. If I use .432 boolits I can shoot powder puff loads with no leading. I have shot as high as 10 grains with great results.
I much prefer 4227 over unique for anything over 1000 fps.
I think your alloy is fine, just may need a .431/.432 boolit.
Tony

[sharps4590]

My experience echo's what ABJ said. Only difference my revolver was 45 Colt. Same thing applies however.

[P Flados]

Out of curiosity I ran a 9 gr Unique / 245 gr cast bullet load through Quickload & got a chamber pressure of 23 ksi.

Although the burn rate of 4227 is slower, you ran a range of loads so I went looking for a charge that would give the same pressure. I found that it took 20.5 grs.

So, the difference has to be in how fast the pressure ramps up, not the peak itself. Searching for other factors to reduce leading likelihood in general sounds like a good idea.

[nawagner]

Probably related to the hardness of the bullet. Given the pressure P Flados mentioned from quickload the Unique would indicate the optimum hardness of about 18 BHN.

It’s possible it is the size of the bullet is partly to blame but I don’t think it is the main culprit because the size of the bullet hasn’t changed in your two situations. Do the bullets pass through each throat of the cylinder with finger pressure only?

[Bazoo]

My throats all measure between .432-.4325. My bullets drop through. I feel a slight tight spot at the threads when slugging the bore. I have several threads on it. I hadnt considered that the pressure of the unique load might not be optimal for my lead hardness.

Up until now, I've not run magnum level loads much because I'm still learning to handle them. I made a couple boxes with 21 grains of IMR 4227 and have shot something like 30-40 of them and still no leading. If I can get some special level loads that don't lead, that will be nice.

I appreciate everyone's input.

[Larry Gibson]

The Unique load gives a faster time/pressure curve with a higher peak pressure. It is also probably obturating the bullets to fit the .432 + throats. The bullets as they enter the barrel forcing cone are then being sized down to a probable .429 and then les as they travel over the lube in the bore. That initial sizing back down is occurring right where the leading at the beginning of the rifling where it is .429 while at peak pressure at that point. The lead drive band or full diameter of the bullet front edge is probably also slightly obturating to fit the larger forcing cone. The leading is from the alloy scraping or smearing off the bullet as all this occurs.

The 4227 load isn't hitting its peak psi with its slower time/pressure curve until the bullet is already inside the barrel and supported by the barrel so no further obturation can occur. Given the low rise to pressure the .430 bullets are probably not obturating in the throats and, thus, are not scraping or smearing any alloy off the bullet as they are sizing down much less under much less pressure. Hence, no leading.

[Norske]

Ol' Elmer often said that Unique melted the base of non-GC bullets. That's one of the reasons he preferred 2400. Having used both powders often, I say he was right.

[Bazoo]

I appreciate those comments. I had not considered the peak pressure timing.

I have some 44 special level loads with bullseye (no other change) I've shot too but without cleaning so I couldn't tell much of a difference. I'll see about cleaning it and how those do.

I had shot some special level loads with bullseye and the lee TL430-240-SWC and they leaded down the whole bore. They were the same alloy and tumble lubed. But they were .428 on the smallest measurement.

Shooting the 4227 loads after those cleaned the bore. I find it amazing how one load or another will actually clean the bore instead of add to the leading.

[ddixie884]

Ol' Elmer often said that Unique melted the base of non-GC bullets. That's one of the reasons he preferred 2400. Having used both powders often, I say he was right.

That may well be right. Elmer liked Unique and used a lot of it but not for any of his heavier loads........

[alfadan]

I think a slower powder may cover up issues with undersized bullets, simply due to less or slower-peaking pressure.

[curioushooter]

Ol' Elmer often said that Unique melted the base of non-GC bullets. That's one of the reasons he preferred 2400. Having used both powders often, I say he was right.

Unique is good up to a point. I have found if you take it to the Keith type pressure range (25kPSI) it causes some leading. Unique shines in lower pressure applications. The Skeeter load is excellent. Around 8 grains with a 260 grainer is about the limit. With the 429215 (a GC bullet) it is outstanding.

I cannot for certain verify it melts the base because when I recover the bullets shot into sand or gel they look almost like they haven't been shot.

[DougGuy]

Next I'm going to try ww bullets sized .431. Then if that still leads with unique, I'm going to try 50/50 alloy.


50/50+2% was going to be my suggestion but you beat me to it. Size to the throats. Of course you can try anything, and there is no guarantee something won't work until you try it you would be surprised by things that aren't supposed to work but do!

I have pretty much ended up with soft alloy/soft lube in every revolver I use cast in, and I have not cleaned a bore in years and years. Some are GC and others not, if I push a patch through the bore I get dark gray almost black with powder and lube residue but no lead that I can see. Elmer was right. 20:1 for most revolvers and 16:1 for magnum loads. I don't know how close 20:1 and 50/50+2% are but you can scratch both with a thumbnail, and I use Felix lube when I can get it, SPG, and Randy's TAC1. They all work.

[Bazoo]

I have tried both ww+sn, and 50/50 ww/Pb +sn, sized .431 and bullseye for a special level load. It leaded. .431 will push through my throats with moderate effort. A slug from the bore will drop through.

I'm considering my options including selling it and finding a 41 magnum. Sept I ain't set to load for 41 and stuff is so hard to get, but no matter, I'm pondering it. Be interesting to see what all the fuss is about.


I haven't tried the unique yet with the 50/50 bullet, but I plan to shortly. I also have bought a gas checked bullet mould. Figure I can shoot the lead out between tests and not have to stop to clean. Though my ultimate goal is plain based bullets with no leading.

Course if y'all remember this gun, it leaded fiercely and I sent it back to Ruger and they replaced the barrel and cylinder. I've not tried lapping it or anything else, just seeing if I could get it to shoot by experimenting with the ammo. Slugging the bore I feel a constriction at the threads. However it isn't horrible and I'm considering fire lapping it. Also considering learning hand lapping.