Vigilance Rifles®

M18 V440

Vigilance Rifles® V440 Cartridge - .440 diameter bullet, using the 50 BMG cartridge as parent case.


The angle of the shoulder and the length of cartridge remains the same as 50 BMG.

The neck is simply squeezed down to accept 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


Available for Windrunners M96 through M18.

The cartridge is nearly the same as 50 BMG, using the same head space gauges.


Fits and feeds from you 50 BMG magazine.

We offer re-barreling of 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.

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.

Only 2 shock waves on a RBBT bullet.