Load Density, Bullet Jump, Case Air Space

MagnumManiac

Well-Known Member
Joined
Feb 25, 2008
Messages
4,185
MagnumManiac, can you please explain the ‘swirl charge’ method
Dump your powder charge into your scale pan, then with a funnel over the case mouth, you hold the scale pan at an angle to the funnel and pour the powder so it makes a continuous tornado like funnel as it swirls into the case. It is even better packing scheme than a drop tube, have tested this side by side and the powder swirled in is lower in the case.
MM: how do you address extruded versus ball powder in your method?
I use the same method regardless of powder type, as in quite a few of my cartridges even ball powder is compressed and it makes a little difference with bulky powder like 760, 780 and US869.
For example, my 375 Bee with a 260g Accubond and 91g of 760 is heavily compressed, so much so that at 92g it forces the bullet back out overnight in the tray. At 91g, if I decide to pull bullets as I did some time ago because I needed that brass for a different bullet to qualify for our big game rifle club charging buffalo shoot, I had to literally dig the powder out of the case for the first 1/3 of it. Never had an issue shooting it like that, but just for safety I backed off after that to 90g. Still gets above 2900fps so I am content with that.
Another example to packing scheme, double base powders behave differently when compressed slightly, there seems to be less variance and a smoother pressure curve. My 338WM with RE19 behaves differently when compressed using either 225g Accubonds or 250g Partitions. The pressure curve under MAP is gentler and the start pressure is higher. Also a simple primer swap from a WLRM to a Fed 210Match gave me even lower ES/SD numbers. I was surprised but delighted to discover this.

Cheers.
 

asd9055

Well-Known Member
Joined
Nov 15, 2013
Messages
1,607
Location
Texas
Dump your powder charge into your scale pan, then with a funnel over the case mouth, you hold the scale pan at an angle to the funnel and pour the powder so it makes a continuous tornado like funnel as it swirls into the case. It is even better packing scheme than a drop tube, have tested this side by side and the powder swirled in is lower in the case.

I use the same method regardless of powder type, as in quite a few of my cartridges even ball powder is compressed and it makes a little difference with bulky powder like 760, 780 and US869.
For example, my 375 Bee with a 260g Accubond and 91g of 760 is heavily compressed, so much so that at 92g it forces the bullet back out overnight in the tray. At 91g, if I decide to pull bullets as I did some time ago because I needed that brass for a different bullet to qualify for our big game rifle club charging buffalo shoot, I had to literally dig the powder out of the case for the first 1/3 of it. Never had an issue shooting it like that, but just for safety I backed off after that to 90g. Still gets above 2900fps so I am content with that.
Another example to packing scheme, double base powders behave differently when compressed slightly, there seems to be less variance and a smoother pressure curve. My 338WM with RE19 behaves differently when compressed using either 225g Accubonds or 250g Partitions. The pressure curve under MAP is gentler and the start pressure is higher. Also a simple primer swap from a WLRM to a Fed 210Match gave me even lower ES/SD numbers. I was surprised but delighted to discover this.

Cheers.
Thank you sir! I appreciate your sharing. This is why I love this forum. Always something new to learn.
Again thanks
 

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