My Ruger Blackhawk 38/357 prefers cast to be sized .357" . a 150 grain boolit, 50/50 COWW - soft lead, with soft Lithium-beeswax lube over 5.2 grains Unique ( 38+P load) shows no leading.
Give the .357 size a try and make sure your lube is a good one . I believe soft lubes work better than hard lubes in these applications .
Gary
Certified Cajun
Proud Member of The Basket of Deplorables
" Let's Go Brandon !"
Have tried both .358 and .359 and the 359's shot best. I also run 50/50 alloy so maybe it being a little softer is why I have no issues with the size.Originally Posted by Petrol & Powder
I never did like BAC either, although it seemed plenty soft to me. I didn't like it because it didn't seem up to the task for high pressure handguns and rifles. 50/50 lube is such a crumbly mess, I'd hate to resort to that. Being as it is essentially a 38 special +P load, I can't imagine there is a huge demand on the lube, but who knows. It is easy to try others. If you have some Alox lube, you can try tumbling the bullets you already have lubed.
It depends on your throat diameter, and bullet design. If your front band is long enough to extend into the throat, and your throats are .358", then your .359" bullets wouldn't fully seat without force. Chances are your throats are that big.
I bet that being swaged down going through the throats puts a demand on the lube that we don't understand. Or at least I cannot understand at present. Lube does funny things.
The fact that I have less leading with the RCBS bullet vs the lee I'm inclined to think it's a lube issue. My guess is the RCBS uses twice the lube judging by the use of my Lyman 450s handle. So my first step will be changing lubes.
That 50/50 is mighty soft. But I have taken to storing my lubed bullets in foam cartridge trays to prevent lube from getting on the noses.
The oversized bullets aren't hurting anything. You're talking about .0005". It's likely you can push those bullets through your throats with only minor effort. Did you ever pull a loaded bullet and measure it? Someone had mentioned thread constriction again. If you did have a constriction, the first 1" of the barrel would be spotless.
I disassembled a loaded round. The bullet was mystery alloy but softer than ww substantially. It still .358. Same batch of winchester brass was used through all.
It will not push through a cylinder throat with all the thumb pressure I can give though it barely will start.
Slightly off subject, I've had ongoing leading issues with my super blackhawk. After a trip to Ruger it's experiencing similar leading as the GP100. BAC lube there too. Be an interesting test if a change in lube cures both.
The throat is nothing more than the last sizing die the bullet will pass through before it reaches the barrel.
If the throat is .357" and the bullet is at least that diameter, the bullet will be .357" after it leaves the cylinder, even if it started as .359"
Just because a cartridge with a .359" diameter bullet will chamber, doesn't necessarily mean that bullet will still be .359" when it exits the cylinder.
Last edited by Petrol & Powder; 06-10-2020 at 10:29 AM.
I know those things petrol, But I'm wondering if the bullet being swaged down in the throats will contribute to my leading issue. Maybe it's squishing some (too much) lube out of the grooves? I do have some lube in the end of the chambers.
When the bullet is swaged, the grooves are narrowed and the bullet elongated as the driving bands are compressed. Lube, like liquid won't compress, so where does it go? I'm thinking that it might be making enough of a difference.
I used this method for measuring my GP100 slug
Sig, I agree, If you have a V-block, that's your best bet.
Are you getting a lube star on your muzzle?
Due to the price of primers, warning shots will no longer be given!
I've tried .358 and .359 bullets in my GP100 and others. My GP100 has .357 throats and I have never been able to tell any difference between .358 or .359 diameter bullets. Either way the bullet leaves the throat .357. I don't think it makes any difference if it's the throat or the sizing dies is sizing the bullet down that final .001/.002. The charge hole tapers from the brass diameter to .357 and I've never had a problem using .359 bullets.
If there's a bore constriction at .354 or .355ish I don't think any small variation of sizing will make any difference. Taking care of the bore restriction will be what fixes the leading problem.
No, the sizing down in the throats does not cause any problems. Lube pumping is what you describe, and is one method the lube gets around the bullet when fired, which is a good thing. The rifling displaces much more lead and lube than the .0005" or so your throat is.
While I'm sure it is possible, my own experience with a bore constriction left the first part of the barrel sparking clean, and then abruptly turned to a sewer pipe right after the frame. If you can't feel anything with a tight cleaning patch, and you are getting even fouling from start to end of the barrel, I wouldn't think you have any notable constriction.
A different lube is worth a shot. A lot of people use BAC with no issues, but I was not one of them. I too got leading, which I blamed on it being an improper lube for the very high pressures I was running. If you don't have any other lube, White Label Lubes sells a sample pack of everything they make.
Sig, thanks but I can't do math like that.
I am getting a lube star.
I can't feel anything with a tight patch but I do feel a constriction when I push a slug through.
I have made and fired 50 rounds with the changes of 50/50 lube and .357 diameter bullets as opposed to BAC lube and .358 diameter. Leading was reduced but still present in the bore. I'd say it was reduced by 50%. Forgot to mention, I had leading in the cylinder throats. I don't understand this.
Also the .357 bullets will push through my cylinder throats, where the .358 would not.
Last edited by Bazoo; 07-14-2020 at 08:10 PM.
You may want to try powder coated boolits at this point. Size them to .357 after coating. If your problem is a roughly cut forcing cone this may not work either. Maybe use a dentist mirror to get a good look at it. I had that problem with a 4" SP101 and I sold the gun to a buddy who shoots only jwords.
"If everyone is thinking the same thing it means someone is not thinking"
"A rat became the unit of currency"
I fire lapped it, 36 rounds 220 grit and 12 320 grit.
I made a box of magnums with W296 powder, RCBS 38-150-SWC WW+Sn sized .357, 50/50 lube. Fired them and no leading in the barrel. Only very minor leading at the forcing cone. Very much improved.
Switched to some specials I had with BAC lube and leading began in the rifling after only 6 shots.
Last edited by Bazoo; 04-05-2021 at 09:57 PM.
Feels good hugh? Nothing more frustrating than a revolver that leads up.
"If everyone is thinking the same thing it means someone is not thinking"
"A rat became the unit of currency"
Yessir, real good. I measured some of the groups I shot yesterday, at 20 yards, 1 1/2". I was having a bad day yesterday for my eyes and hands. I was able to cloverleaf some of them but not a whole 5 or 6.
Posting Permissions
| BP | Bronze Point | IMR | Improved Military Rifle | PTD | Pointed |
| BR | Bench Rest | M | Magnum | RN | Round Nose |
| BT | Boat Tail | PL | Power-Lokt | SP | Soft Point |
| C | Compressed Charge | PR | Primer | SPCL | Soft Point "Core-Lokt" |
| HP | Hollow Point | PSPCL | Pointed Soft Point "Core Lokt" | C.O.L. | Cartridge Overall Length |
| PSP | Pointed Soft Point | Spz | Spitzer Point | SBT | Spitzer Boat Tail |
| LRN | Lead Round Nose | LWC | Lead Wad Cutter | LSWC | Lead Semi Wad Cutter |
| GC | Gas Check |
Reply With Quote