The other thing might involve more of a crimp will hold the bullet for that split second longer and can change a dirty burning charge into an acceptable one...sometimes. If you're not crimping heavy, that would be something I'd experiment with.
The crimp is a little tricky for me. Its always seemed very subjective to me, and pictures havent helped much. It doesnt help that these bullets are hornady and have no crimp groove. The lead is just very soft and you crimp into the side of the lubed lattice looking area.
Not gonna comment on powder charges, but a lot of so called powder "fouling" is actually the lube on lead bullets.
This is happening also, but its separate. I guess hornady lubes all of their bullets with a dry powder lube. It does what its supposed to, but it does make a light cloud when you shoot.
Is there any chance the powder was contaminated? Could you dump out the powder in the hopper and load some test rounds with fresh powder from the bottle?
These were all loaded from a fresh bottle. No powder measure was used. They are scooped directly to the scale.
- What is your groove diameter of the barrel?
- Is your leade/freebore extra long?
- What OAL/COL are you using?
- Are bullets way undersized for your barrel?
- How much taper crimp are you using?
- Is your scale properly calibrated and do you have check weights to verify accuracy?
-No idea on the barrel dimensions. Never really looked into slugging it.
-Long Leade? Its a 357 and these are 38 special, so there is that jump. Other than that, its a factory revolver. I see no reason why it should be excessive.
-Bullets all seem to be between .357 and .358
-The crimp is a roll crimp and I think maybe a medium crimp, but Im a little fuzzy on that. see above.
-The scale is an RCBS beam scale, calibrated at zero per the manual. I dont have check weights, but theyre on the list.
These were crimped with the hornady seating die that I have. Separate step from the seating. Seated to 1.450" per Hodgdon and the hornady manual. No FCD was used, though I just bought one. Havent tried it yet.
Regarding max loads, that 4.6gr charge is listed as max from Hodgdon, but the Hornady manual goes all the way up to 5.3 for a max. I made a whole range of loads to test going from 4.0gr up to 4.6, figuring that the more conservative data would probably be better, but they all behaved the same way. Maybe 15,000psi just isnt enough for the powder to work properly. All the other major calibers I see that use it have higher max pressure. Maybe using a jacketed bullet would make the difference.