VV N330 for .357 Cowboy Action, load data 3.9gns ?

[coolforgot]

Hi

I've just switched from using Alliant 2400 (13.8gns) to VV N330 which the Vihtavuori site load data gives a starting load of 3.9gns

this load seems very small in the 357 case, aprox 1/4 full, (158gr lswc)

after being used to 2400, the N330 load looks an innsufficient ammount by volume in the case (light load ?)

I'm sure the load data is correct,can somebody (who's used/uses N330)comfirm this to me.

Also the V V web-page load data states to use Small RIFLE primers NOT small Pistol primers ???

I have emailed them to ask if this is correct ? or have they made a printing error !

 

I have copied/pasted the data off V V below for you to confer :- ( I know it says Barrel 6",but the data is the same for cowboy action)

 

".357 Magnum

Test barrel: 150 mm (6”), 1 in 18½” twist
Primers: Small Rifle
Cases: Remington, trim-to length 32,60 mm (1.283”)"

 

Awaiting your replies, Mike

[phaedra1106uk]

That load looks fine, I use around 3.4gr of N310 for sub-sonic 300aac and 4.9gr for sub-sonic 308Win using 115-165gr cast boolits, both using rifle primers.

 

As for the case fill volume, this is from Viht's powder information,

 

2) Free space in the case
When using charges which leave large amount of free
space in the case, the shooting characteristics may vary
largely depending on where the powder is located in
the case. If the powder lies totally in the bottom of the
case (i.e. in the end where primer is), the muzzle
velocity and especially the maximum pressure become
much higher. The maximum pressure may even be
doubled when same powder charge is moved from the
bullet end to the primer end of the case. This can
simply be demonstrated by shaking the revolver barrel
upwards or barrel downwards just before turning it
smoothly in horizontal position, aiming and shooting.
Also the recoil may transfer the powder in either end
of the case. This is sometimes seen as a velocity change
between the first shot and the following shots.
The shot to shot deviations in velocity and pressure
are normally increased when using load which leaves
the cases half empty. For this reason such loads are not
recommended for target loads. The data below is
tested in a way that the powder is as much as possible
in the primer side before firing, and therefore, the
pressures and the velocities represent the maximum
values which were obtained using our test equipment
and cartridge components indicated in the table.