While the 20 ga. Mossberg Shockwave may drive ammo companies to produce low-recoil/still effective defense options, it's not happened yet. That's why the 12 gauge still predominates.

I was watching a video from Chris Baker at Lucky Gunner about the 20-gauge shotgun as a defense gun. You can see him give his conclusions for yourself. I find myself in agreement with him.

I’d gotten some hope late last year on the potential for new 20 gauge ammunition at a media event Mossberg put on at Gunsite. Among other things, we were introduced to the 590 Shockwave in 20 gauge.

The 590 Shockwave in 20 gauge is the first 590 20 gauge in the line. I wrote at the time that I hoped they extend that to a real 590A1 in 20 gauge. The 20 gauge Shockwave weighed less than the 12 gauge Shockwave – but the big problem was ammo.

12 gauge ammunition is very well developed, unlike the 20 gauge. Until ammo companies step up to face that problem – and I think the Shockwave will help drive that process – the 12 gauge will remain the go-to shotgun round for defense and LE applications.

Meanwhile, the pistol-caliber carbine races to the forefront. If you don’t like to get kicked around by the fowling piece – or if you can’t afford to be kicked around for medical reasons, the PCC could well be the answer.

The problem with pistol caliber carbines is the same as the advantage of pistol caliber carbines: they shoot pistol ammunition. While your ability to precisely direct the projectile where you need it to go – and you can do so quicker, with less blast and felt recoil – it’s still a pistol bullet.

Pistol bullets are designed to be driven at an optimal speed. Pistol cartridges are formulated to burn their charge in a shorter barrel, getting full and best use of that charge in barrels far shorter than the 16” minimum mandated by the silly National Firearms Act of 1934.

The optimal velocity for pistol bullets is one at which they’ll perform to the FBI standard using just the right gelatin under the right conditions. We can debate the protocol but it’s a documented standard of achievement.

Pistol-caliber carbines, like the Ruger PCC, can fill the long-gun need but the question is how the pistol rounds perform out of longer barrels.

An expanding bullet that’s overdriven can expand quickly, even fragment in the media, limiting penetration. A round that penetrates in a shallow fashion may not stop the fight.

I don’t play in ‘jello’ and the range I use limits the targets I can use. I can check velocities and thought that would provide a part of the answer.

The test gun was a Ruger PC Carbine. With some of the loads, I checked average velocities against a 3.6” pistol barrel fired at the same distance.

Velocities: Ruger Pistol Caliber Carbine, 16-inch barrel

41° F, 56% relative humidity. Chronograph ten feet from muzzle

As you can see from the data, conventional pistol rounds gave up around 200 feet-per-second – not a lot. The hyper-light/hyper-fast rounds had more to give up, but tended to give up proportionally about the same amount of speed. How the different rounds would actually work in the ballistic media or in an actual incident is open to question. I imagine someone will test the difference in ballistic media eventually.

Is it worth it going from pistol to pistol caliber carbine? Depends on what you’re trying to accomplish. My best effort with irons was three hits inside three inches or so at fifty yards with the Ruger PCC. I’m sure that’s beyond my ability with a 9mm pistol.

Some shooters will find that the pistol isn’t a good plan for them in the defensive context. It’s all about choice.

The 9x19mm is not even up to 30 Carbine-class and some complained about the M1 Cabine’s ability to stop fights in previous unpleasant contexts.

Meanwhile, I still hope that the 20 gauge will be developed into a more useful defensive implement by our ammo and gun makers. For our changing demographic, it would be a smart move.

-- Rich Grassi