The 375 Viersco Magnum was developed for the super long range" Hard Target Interdiction" rifles.
The case is a proprietary design taken from my original 416VM or Viersco Mag for short, I totally
redesigned the case from the bottom up. It now has more capacity and features an extended neck
so that ANY bullet can be used with a standard throat set up.
Follow along as we go through the design process and testing of this new case.
375 VM2
Improved case design
short or long neck versions
Sharper shoulder, 40 deg.
Initial tests... Check out the 375 VM test page

375 VM2 with 375gn Cutting Edge Bullet... over 9000 pounds of muzzle energy!
Actions,
This case needs a bolt body of at least .750 with a bolt face of .690 to work properly. Most of the larger
custom actions can be modified to accept the large cases. Ejection port work might be needed on some
models. Barker Machine Works will be offering a modified action just for the VM cartriges.
Rifles,
What is nice about the Viersco Magnum is that you can build rifles that will out perform the 50 BMG
in a package that can be carried in the field for hunting or long range shooting.
It is possible to build the complete system under 16#, single shots only. Repeaters are not
available at this time due to the length of the loaded round ( 4.600"), it will require a special action.
Reloading,
The case takes standard reloading components, large rifle mag primers and slow burning powders. The reloading dies are either 1 1/4"x12 or 1 1/2"x12 threads, depending on what
press make you have. Standard dies to benchrest types are custom made to order.

375 Viersco Magnum test rifle pictured above, featuring the XLR Industries aluminum stock.
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Larger Viersco Magnums
416 Viersco Magnum
The original design is also available for the 416 caliber shooter. This rifle is well suited for extreme
long range shooting or for African Dangerous Game. This case differs slightly over the 375 version
as it has a sharper shoulder and standard neck length. The overall length of the case is 3.040, and will accept most of the 416 cal. bullets available. This chamber will produce close to 9000# of muzzle energy.
458 Viersco Magnum
Necked up version of the 416 VM case, Shooting 500+ grain bullets this one has over 10,000# of muzzle energy.

Picture of comparisons with other chambers