06/03/2026
As many of you have heard Proof Research introduced a new take on gain twist barrel rifling which they're calling PXT. Where a "standard" gain twist barrel may start at 1:11 at the throat end up at 1:7 twist at the muzzle, PXT barrels would start at 1:250 at the throat and end up at a 1:7 twist rate at the muzzle. For those interested I'd recommend taking a look at Proof's website for more information - they do a great job explaining the tech.
Why does this matter for fast twist monolithic subsonic projectiles? Here are some shower thoughts:
We consider fast twist barrels to be barrels with twist rates of 1:5 twist or faster rifling. Subsonic ammunition with long monolithic projectiles in particular (like what Discreet uses) benefit from fast twist rifling. We have observed that both external (bullet flight) and terminal ballistics (bullet impact) benefit from increasing subsonic projectile RPM using fast twist barrels. However, with internal ballistics, which is the study of the processes and forces acting upon a projectile while it is still inside the firearm, the benefits of fast twist rifling are few and far between. Precisely designed machined bullets like our Selous line must overcome violent angular engraving forces during initial shot start with a fast twist barrel. This engraving force puts a lot of radial stress on the bullet, and any expanding bullet must be properly designed to accommodate these forces.
Using tech like Proof's PXT could really change the game for fast twist subsonic. Rather than the abrupt angular force during initial projectile engraving, the PXT twist would gradually impart rotation on the projectile as it travels towards the increasingly fast twist rifling closer to the muzzle. It's like slowly boiling a frog, but with bullets.
Similar to non-traditional silencer designs that we're seeing with today's additive 3D printing, PXT has the potential to open up projectile design possibilities in the future. One of the goals of Discreet Ballistics is to continue converging signature reduction and lethality. We've come pretty far with it already, but seeing exciting new tech like this reminds us there's still further to go!