The news of a potential revolution in the design and manufacturing of rifle barrels came from the United States on May 21st: PROOF Research announced the launch of the new PXT "PROOF eXponential Twist" line of barrels for long-range precision shooting rifles, precision hunting rifles, and semi-automatic modern sporting and tactical rifles.

The development of the new PXT barrels stems from the use of high-pressure cartridges to satisfy the need to deliver significantly more energy on target for certain applications; this, however, is cause of higher levels of wear on barrels.

In a conventional barrel, the bullet is forced forward and abruptly engages the rifling at roughly a 6° angle, starting to rotate at full speed within the first quarter inch of travel. This creates a sharp pressure spike, accelerates barrel wear in the first two inches of the barrel, and places significant stress on the projectile.

PROOF Research found a solution in the form of an explonential twist rate that begins far more gradually before accelerating through the bore, and features a smoother-edged profile rifling and a dramatically reduced initial engagement angle. This reduces bullet engraving force by approximately 30%, limiting deformation, reducing wear on the lands, and enabling a more gradual twist progression.

Reportedly, this results in a 95 through 98% reduced lead angle, for lower throat erosion and pressure spikes; and a 30% thru 100% longer barrel life before accuracy degradation, depending on barrel length (the longer the barrel, the higher the service life).

PXT barrels have also shown measurable improvements in consistency and accuracy. Across multiple ammunition types and lot variations, PROOF Research observed repeatable 20 thru 50% reductions in group sizes in controlled testing.

The concept of exponential twist rate isn't exactly a new thing – a gradual twist was first used in the mid-19th Century to avoid deformation of soft lead projectiles – but PROOF Research is the first company to apply it on an industrial scale and from the standpoint of barrel longevity.

Up to very, very few years ago, such innovation would have been near-impossible to introduce, as the implementation of gradual increasing twist rates would have created an unacceptably high reject rate for accuracy-destroying imperfections with any manufacturing method known.

The relative advantage enjoyed by PROOF Research is that any reject rate would apply to a thin, relatively cheap barrel liner that would be rejected prior to the expensive process of carbon fiber jacketing.