I'm shooting a cartridge Call the .30 HART. It is an Ackleyization of the 300 Weatherby cartridge. It is the invention of the good people at R.W.HART & Son Inc., of Nescopeck PA. They have suggested that RL19 powder be used in their cartridge with bullet weights from 180 gr. to 210 gr. It works fine in the accuracy department but is prone to changes when the temp. goes up and down. Example 81 grains of RL19 and a 180 grain Nosler Ballistic Tip bullet will work great in temp.s that are below 70 degrees F. However in the heat of the summer this load will lock the bolt and blow the primer pockets to hell and gone. I have had to drop back to 78 grains of powder and things are working fine again. Problem is obvious. You just can't load some cartridges and have them on hand till you check the temp. outside. If you know of a more stable and siutable powder for this type of cartridge please advise.

Sounds like you might need to try H4831SC which is made here in australia, our powders are designed to handle the extreme variations in temp that we live in.

The other one you might try is H1000 which is also and Australian powder that we call ASDI 2217.

About like Reloader 25 in burning rate.

My limited use of Re 19 and Re 22 has shown that it is susceptable to pressure spikes even from powder fouling.

Mike

Sometimes the Hodgdon claim of temperature insensitivity is true, and sometimes it's not. It varies with case capacity. In the .308, for example, Varget has approximately a zero temperature coefficient. In the .223, it does not.

You may find that one Hodgdon powder works well, and that another does not.

I've been told by people who seem to know that double base powders are more temperature sensitive than single base powders.

You may want to give IMR 7828 a try. Hot loads are hard on actions in those large capacity cases. Your very lucky you did not stretch the action shooting those hot loads.