SG Ammo still has 50 round boxes of HST last I checked.
Regardless, their website states this:
Heavy Mass Ammunition
Seismic ammo is taking conventional ammunition in a different direction. We believe a projectile with more mass traveling at a slower speed is more effective then a lighter weight projectile traveling at a higher speed and has less risk of over-penetration. Our 185gr 9mm +M ammo is now available and we have other offerings coming soon.
https://seismicammo.com/Bottom line is that's simply not the way modern HPs work -- expansion of all modern hollow points is very much velocity-dependent. And b/c slower bullets typically expand less, they typically penetrate deeper. For high mass bullets like this, it substantially increases the risk of over-penetration, excepting only those cases where the bullet strikes bone (even then, heavy bullets more likely to break and fragment bone and then continue to penetrate). It's basic physics and terminal ballistics.
Further, penetration is only important for those calibers that already lack sufficient penetration... 9mm in 124 gr+ self-defense bullets already has sufficient momentum to achieve FBI specs as do all larger calibers. Perhaps in smaller calibers like .380 this concept might make sense (.380 ball exceeds FBI minimum penetration specs IIRC) -- but that's about it as I see it...
Now, if we're talking using pistol calibers in place of say .300 blackout, then yeah, this bullet probably has a niche in a hog, deer, etc, suppressed hunting setup.
Effectively, Seismic is rehashing the .45-70 vs .30-06 debate with this cartridge...
https://www.quora.com/What-ammunition-is-more-powerful-30-06-or-45-70Where this whole momentum-first concept comes from is the archery world where arrows are traveling MUCH SLOWER than even subsonic bullets.
https://www.nockout.com/understanding-the-momentum-and-kinetic-energy-of-arrows/And if you want to get really far into the details:
https://cpw.state.co.us/Documents/Hunting/EHU/Momentum-KineticEnergy-ArrowPenetration.pdfLastly, where I'm personally concerned with momentum is when it comes to intermediate barriers, penetrating concealment, and turning cover into concealment. For instance, 120gr 7.62x39 or 140 gr .308 is much better at turning cinderblock into concrete dust than is 55 gr 5.56, etc. And to that end, I'm sure Seismic's 185 gr 9mm will perform great against auto glass, but then Lehigh Defense's new lightweight (90 gr in 9mm) all copper rounds that create permanent would cavities via hydraulic forces also perform superbly against auto-glass -- it's as much about bullet construction as weight...
Regardless, unless one is hunting heavy-hided game and needing to do so suppressed and subsonic -- I'm personally grouping this offering with G2 RIP until I'm proven wrong. And fwiw, Dixie Slugs already makes 700+ gr 12g shotgun slugs, but standard shotgun slugs kill bear and moose, and have probably killed a fair number of dangerous African game too -- after all, the 10g/12g is the poor man's elephant gun...
