460 S&W and Quickload/GRT error

[Mrvmax]

Was going to try out the new AutoTrickler V4 this weekend with the 460. Looked up load data in my Hodgdon manual and Barnes for the 275 grain XPB. Their starting load shows over max pressure in QL and GRT. Actually every load manual I own, Hodgdon, Barnes all show the same load weight.

I called Hodgdon and they said they don't recommend QL and that they actually test all their loads so it can be trusted.

I've never had QL be so far off, QL matched load manuals with H110. Anyone else have this happen? I run every load through QL and go to GRT if needed. I've only had one other load be off, a 10mm load.

I'll start with lowest powder charge and watch for pressure signs but I'm leery now.

 

[Mrvmax]

Should have mentioned, using NO 9 powder

 

[MKWas]

The readme file that comes with QuickLoad mentions that there are issues with large straight wall cartridges due to issues accurately modeling powder burn in these cartridges. Their examples are 458 Win Mag & 45-70. I would think the 460 S&W would suffer from the same issues.

They give some direction about tuning QT for these cartridges.

 

[Mrvmax]

QL was correct, Hodgdon (and all my manuals) were incorrect- at least for me and my revolver. I made some ladder loads stepping up to the max loads Hodgdon listed. I only got to the second out of five and saw pressure signs.

 

[Mikecr]

issues accurately modeling powder burn in these cartridges..

The issue is that much of the powder forms a slug that travels with the bullet down the bore. This adds mass to the bullet, while changing burning parameters. I can understand why this would be very hard to predict, but can be tuned with 'weighting factor'.

 

[MKWas]

The issue is that much of the powder forms a slug that travels with the bullet down the bore. This adds mass to the bullet, while changing burning parameters. I can understand why this would be very hard to predict, but can be tuned with 'weighting factor'.

This is always the case. The mass of the powder is always expelled from the barrel, either as gas (burned powder) or as solids (partially burned or unburned powder). Energy from the powder burn is needed to expel the powder and must be considered for interior ballistics.

Bottle shaped cartridges create turbulence inside the case and as it exits the case. This promotes better mixing of the hot gas & solids, so there is more efficient combustion. Energy is still used to expel the powder, but in this case the more efficient combustion of powder creates more energy from a given mass of powder.

 

[Seabeeken]

The readme file that comes with QuickLoad mentions that there are issues with large straight wall cartridges due to issues accurately modeling powder burn in these cartridges. Their examples are 458 Win Mag & 45-70. I would think the 460 S&W would suffer from the same issues.

They give some direction about tuning QT for these cartridges.

This is true. In grt you have to set cylinder gap on revolver data. Not sure about ql. Straightwall pistol loads are a frequent question at grt.