Leading in .357 Flattop

[ebg3]

I went out and shot my .357 today, it is a 4 5/8" anniversary flattop black hawk. My load is cast Keith boolits that weigh 172grs after being sized and with Felix lube. I'm using 14.3 gr 2400 with Win. small pistol primers and I trimmed the brass to 1.265" so the load would fit in the cylinder. I thought my crimp was heavy enough but after 4 shots, the 5th and 6th have jumped a little. The load chrono's about 1325fps and accuracy is pretty good. All that being said, after firing 50 rds, I checked the barrel and see that it is leading up. the first two inches from the forcing cone are free of lead and shiny clean, but from 2" to the muzzle there is a film of lead/fouling building. It's not really bad but it looks cruddy.
The alloy I use is Isotope lead that seems to be very similar to wheel weights and I air cooled the boolits. They are sized with a .358-9" die in my Lyman sizer. I could try to water drop the next time I cast or switch to the Lithibee lube I made before switching to the Felix Lube.
Any body have any ideas? It almost seems the lube is running out.?
Thanks in advance,
Eddie

[runfiverun]

lube.

[Blammer]

lube is the problem

also watch your crimp, you may be crimping too much if htey are still jumping

[ebg3]

Thanks, I didn't think about over crimping. I'll try the lithibee and see if that makes a difference.
Eddie

[ebg3]

Changed a couple things and went out to shoot today. I trimmed all my brass to 1.25" and dropped the load to 14 grs 2400 and adjusted my crimp. I measured at the crimp on my old ammo and found the brass was bulged just a bit below the crimp. I crimped the new ammo just short of bulging and didn't have any boolits jump crimp today, I shot 40 rds. The boolits are still leading even though I reduced the charge a bit. Next, I'll try the other lube and harder boolits. The first two inches of barrel from the forcing cone are leadfree, from there to the muzzle is leaded.
EG

[462]

ebg3,

Hardness isn't the problem, lube is.

[jdgabbard]

The keith carries quite a bit of lube too... Have you cronied those loads???

[HeavyMetal]

Yes try another lube.

[Ekalb2000]

Rugers like big boolits. What size are they droping out from your mold? Try about 25 not sized. You didnt say what your brl sluged at.
Are you pushing them too fast? try starting @ 13gr.
Just another thing to wrap your head around.

[MtGun44]

Throat diam?
Groove diam?
Boolit diam?
Lube type?

Probably undersized boolit or too tight throats making good boolits undersized, or
may just be inadequate lube.

[ebg3]

Boolits are sized just a little larger than .358", I honed a lyman .358 sizer. Cylinder mouths allow boollits to pass through with a little resistance. Not 100% sure on the bore but it is closer to .357. Lube is Felix lube that I made. I do have a batch of 50/50 beeswax moly greese I will try again. I figured undersized boolits would start leading at the forcing cone, the first 2" of my barrel are clean.
The 14.3 gr load was going 1325 from the 4 5/8" barrel. I dropped it to 14 gr and have not chrono'ed but it should be around 1275 fps, I saw no difference in the amount of leading. The lead does easily brush out with 5-6 passes of a bronze brush, this is after 50 rds or so. I'm not trying to push to the max, I just want 1275-1300 fps and not have leading. I will continue to experiment with the moly lube and maybe a harder boolit. Once again, thanks for the responses and the advice.
Eddie

[GabbyM]

You say you're not trying to push it to the max. Although you don't state what bullet you are using a 170 grain Lyman #358429 in the Lyman book shows 13.5 grains of 2400 as max at 41,100 C.U.P. and 1242 fps from a 4" universal receiver. I don't know what book you're looking in but I'd call 14 grains a lot of powder. 12 grains sounds like a better place to start. I'd be hesitant go over 13 grains.

Could this be caused from a barrel constriction where it threads into the frame? Sizing the bullet down.

[44man]

I have no idea what that alloy is like but could it be too soft? Are the boolits slumping so much the grease grooves are being smashed out of existence?
You really need to recover boolits to see what is going on.
Felix is one of the best lubes going but no lube will work if you do away with the GG's before the boolits get down the bore.
Maybe adding tin would help but it sounds like you need alloy work so the boolit can resist slumping.
I just showed this picture a while ago of a Keith being destroyed in the gun.

[RobS]

If you have not slugged your barrel then doing so will clear up some variables. If your barrel is tighter at the throat vs let's say the rest of the barrel then that is likely the issue.

Slugging the barrel will let you feel if there is any tight spots or restrictions in the barrel. Ruger has issues with this from time to time, especially where the barrel screws into the frame.

If there is a restriction in the barrel at the barrel throat:

Your bullet will enter the barrel and then be swaggered down to "fit". As it continues down past the restriction it will have the potential for gas blow by resulting in leading. A fix for this will require you to lap the barrel and work out the barrel restriction if you have one. Another option although not optimal would be to use softer bullets so once the bullet works past the restriction it can then obturate or bump up to seal the barrel. This is going to be tough though in a 357 mag pushing high velocities/pressures with a plain base bullet. A gas check will help if you have this issue as well and is a better option if you choose to not lap the barrel.

I don't know if you have a barrel restriction or not, but slugging your barrel will be a sure way to find out and will also let you see what groove diameter your barrel has. I would also slug the barrel throat to see what you have there too. FWIW

Rob

[RobS]

I just showed this picture a while ago of a Keith being destroyed in the gun.

Now that is a great bullet picture for those who believe that "a soft bullet is just fine and I've done it" at high velocities/pressures.

[Rockchucker]

You say you're not trying to push it to the max. Although you don't state what bullet you are using a 170 grain Lyman #358429 in the Lyman book shows 13.5 grains of 2400 as max at 41,100 C.U.P. and 1242 fps from a 4" universal receiver. I don't know what book you're looking in but I'd call 14 grains a lot of powder. 12 grains sounds like a better place to start. I'd be hesitant go over 13 grains.

Could this be caused from a barrel constriction where it threads into the frame? Sizing the bullet down.

I'll have to go along with Gabby on this one, I'm showing 14 grains as max also for a 170 grain boolit. I get good results with 12 grains of 2400 with a gas check boolit and I 'm sizing to .357 and zero leading in my Black hawk.

[Bass Ackward]

I love the hardness criticisms out the gate. People just can't let go can they?

If you absolutely want the cause for this in a nutshell, it's the fact that he didn't use the first rule of reloading / shooting: start low (slow)and come up.

That's why I have pretty much gone to recommending all beginners to cast and low experienced reloaders for rock hard. Easier to load without errors and wider working pressure range. Then if they still lead, you can push their jaws shut and have their complete and undivided attention because there is no place to hide.

Problem could be the metal. The interior containers can be and mostly are pure lead. The large heavy outsides can be anything on a BHN basis. I have had them from 8 to 15. What hardness are his bullets?

But ALL rifle bullets slump. Even solid copper at 40 BHN that obdurates (changes) starting with 45k psi. That's why BC needs to be calculated AFTER firing. Yet this change still allows for accurate shooting. And Europeans have HV rifle bullets that are semiwadcutter spitzers. So I guess what I am saying is that slumping doesn't have to be a problem.

What is actually funny is that slug with no grease grooves has a MUCH higher BC than the original design. Anyone understanding hydraulics would tell you that that bore is not perfect and loses seal. Otherwise a pure lead bullet could be shot and NOT lose the grooves, no matter HOW much pressure behind it.

Even if you have a tester or bullets hardened by God, you still need to start low and come up. Safety first.

[Marlin Hunter]

Throat diam?
Groove diam?
Boolit diam?
Lube type?

Probably undersized boolit or too tight throats making good boolits undersized, or
may just be inadequate lube.

That would be my guess also.

[ebg3]

When I bought this flattop .357 I consulted Big Bore Handguns and a few articles to find loading data for the Keith 172gr swc. I tried WW296 powder to begin with working up from a starting load and did not like the powder fouling or the velocity. I bought 8lbs of 2400 and first tried the old load of 13.5grs with 38 special brass, the old Keith load, I don't like using the short brass so, I trimmed .357 brass just enough to allow the loaded round to fit the cylinder. I worked up from the 13.5gr load to 14.3 grs watching for pressure and checking velocity. I still don't think the 14.3gr load with the longer brass is quite as hot as the old 13.5gr special load. Now after reading others' concerns about this load being too hot I'm starting to be concerned. I think I'll stick with 14 grs and pursue some of the helpful suggestions that have been posted. The first and easiest is to try the other lube hopefully this will be the fix. I'll follow up when I get a chance. Oh and in the Lyman 43rd edition handbook, they list 14grs 2400 with the 358429 bullet as the maximum charge.
Thanks,
Eddie

[Bass Ackward]

When I bought this flattop .357 I consulted Big Bore Handguns and a few articles to find loading data for the Keith 172gr swc. I tried WW296 powder to begin with working up from a starting load and did not like the powder fouling or the velocity. I bought 8lbs of 2400 and first tried the old load of 13.5grs with 38 special, the old Keith load, I don't like using the short brass so, I trimmed .357 brass just enough to allow the loaded round to fit the cylinder. I worked up from the 13.5gr load to 14.3 grs watching for pressure and checking velocity. I still don't think the 14.3gr load with the longer brass is quite as hot as the old 13.5gr special load. Now after reading others' concerns about this load being too hot I'm starting to be concerned. I think I'll stick with 14 grs and pursue some of the helpful suggestions that have been posted. The first and easiest is to try the other lube hopefully this will be the fix. I'll follow up when I get a chance. Oh and in the Lyman 43rd edition handbook, they list 14grs 2400 with the 358429 bullet as the maximum charge.
Thanks,
Eddie

Eddie,

I have and had several 357s over my lifetime that I have shot up to 16 grains of 2400 with a 358156.

So when I got this last 357, I loaded 12.5 grains and WDWW bullets of 28 BHN and went out only to stick my first cylinder full.

I didn't lead, but I had to wait until the next weekend to fire the second cylinder full. So you are not alone. We all need to be reminded from time to time.