Our brand new V440 Cartridge - .440 diameter bullet that uses the 50 BMG cartridge as parent case. We have kept the angle of the shoulder and the length of cartridge the same as 50 BMG. The neck is simply squeezed down to except the .440 Bullet and have .005 neck tension.


  • The chamber runs a tight neck at .489 - only about .001 clearance with new Winchester Primed Brass.

  • We are offering this Hot Rod Caliber for our Windrunners, new and old. EZ barrel swapping as usual already Head Spaced to your rifle.

  • The cartridge is nearly the same as 50 BMG, we use the same Head Space gauges. Also the big advantage of this cartridge is that it fits and feeds from you 50 BMG Magazine.

  • We will also re-barrel other manufacturers rifles - some alterations to the bolt may have to be  performed.

  • The process takes seconds - all it takes one squeeze, stretching the brass .01, ready to load and fire.

    • We have bullets, dies, and rifles.

    • Full Length / Form Die and Neck-Size only Die, you use your 50 BMG Shell Holder and 50 BMG Bullet seater to push the bullets to the 5.450 OAL.

  • User friendly - we've done all the heavy lifting for you.

    • After first firing, you will need to trim the brass.​



  • .440 Diameter – 2.50 long – 600 gn. RBBT / Rebated Boat Tail – Tellurium Copper

  • Load 225 gn. H50 BMG Max

  • 3125 fps - with 36 inch Chromoly 1:13 twist


The concept of this cartridge comes from the Weatherby Formula, “Jump the Diameter of the Bullet”.

The cartridge was engineered first to those Weatherby specs before going in to production of reamers and bullets. This bullet jumps a .440 length while being confined to a .441 diameter before entering the lands and grooves. Because of this jump, the pressures are reduced and velocity can be increased.


There are different opinions on how to shoot accurately, some say bullet on the lands, others .03 off lands, etc. The conversation can go on forever. Weatherby's formula has worked for us, and we have used it on many of our rifle designs. We'd like to think there are few that would argue that a Weatherby is inaccurate.


So that's how we get 3125 fps with a 600 gn bullet without pressure issues, the brass is very reloadable. We estimate at least 8 reloads, if not more.


First firing after forming brass has provided .625 5 shot groups.

Fire Formed Brass produces even better results below .500 - but it's likely you'll do better than than some of us here at Vigilance Rifles Inc.™.

17.5 MOA up from 100 yard zero to the 1000 yard target - based on that we estimate a 1.1 BC


Check out the pictures below – showing comparisons of several cartridges and specs of the V440.


Also note the multiple shock waves on standard rebated bullets VS.

Only 2 shock waves on a RBBT bullet.






600 gn - 1.1 BC -3125 fps

17.5 MOA to 1000 yards with 100 yard zero

(928) 910 - 3623

4845 N. Spruce, Chino Valley, Arizona 86323, USA

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