Hodgdon Data vs. GRT Data (.357 Mag)

[ARXV]

Hodgdon's data for CFE-Pistol and Titegroup loads is listing pressures much higher (like 10,000 psi) than Gordon's Reloading Tool shows. Is GRT known to be very accurate for pressure and velocity?

 

[Orr89rocz]

Hodgdon's data for CFE-Pistol and Titegroup loads is listing pressures much higher (like 10,000 psi) than Gordon's Reloading Tool shows. Is GRT known to be very accurate for pressure and velocity?

In my experience it can be off and is dependent on alot of variables that need to be correct, such as case volume and bullet dimensions and seating dimensions. Powder stats such as burn rate and densities also sometimes dont match reality. You need to calibrate it by starting with min loads of the same book components and record your actual velocity. If all the case volume and dimensions are set right, then you play with initial shot pressure, powder burn rate, etc to get velocity to match your measured results to “true” it. I havent used it for handguns yet but have in a variety of rifle cartridges from straight wall to overbore bottlenecks. It leaves alot to be desired as an initial guestimate but better than nothing

 

[Webster]

Hodgdon's data for CFE-Pistol and Titegroup loads is listing pressures much higher (like 10,000 psi) than Gordon's Reloading Tool shows. Is GRT known to be very accurate for pressure and velocity?

Remember the manual data is based on real data based on the components used. I don't like computer guestimates , especially since they give incorrect loading data that has to be corrected by fudging numbers to get it to match chrono numbers. Try to lookup data in several manuals and compare. Some companies put loading data free on line. Never try to push the limit. A medium accurate load is the safest.

 

[chromatica]

I pay close attention to the location where burnout occurs. I look for a powder that has a nice range of charges between max pressure and the smaller charge at which burnout happens right at the muzzle. If burnout occurs after that, you are wasting money. I suspect accuracy may also suffer, but I don't know that for a fact. For my 9mm loads in a 4 inch barrel, this interval is often around 1.0 or 1.5 grains of powder.

 

[SeabeeKen]

Grt can be a bit lacking with handgun and straightwall cartridges. Revolvers will have to have the cylinder gap added into grt. Its in the grt manual. It does help. I find grt quite accurate when the input is accurate.you will need to calibrate the powder model with actual velocities.
There is quite a difference in saami pmax and cip pmax in 357 as i recall. I used cip pmax and barnes thought i was nuts but no pressure signs