Lol, no you won't. Go shoot an open tip 9mm at a piece of dry wall, put a 2x4 behind it too. If you place a cardboard target behind that and shoot through them all, you'll see a nice, round hole in the cardboard.
Open tip 9mm fills up with softer media like wood or drywall and behaves like an FMJ with velocity inadequate for expansion or fragmentation.
Expanding 223 is the safest choice of all (especially plastic tipped options). It has the energy to make the projectile expand as designed.
Expanding is not what results in reduced .223/5.56 penetration through drywall... It's tumbling for increased surface area/reduced sectional density when hitting with its side when penetrating subsequent layers of drywall, etc. .223/5.56 soft points/ballistic tips (everything but frangible) and 9mm hps perform quite similarly through drywall.
For instance:
https://www.alloutdoor.com/2018/10/09/drywall-penetration-9mm-vs-223-vs-22-lr/He uses a Glock 9mm in a carbine conversion with a 16" barrel for the 9mm portion of the test. The Blazer Brass 124-grain FMJ (about 1300 fps) penetrated 22 layers of 3/8" sheet rock and dented number 23.
For 223, he uses an AR with Perfecta 55-grain FMJ ammo, which travels around 2800 fps. It penetrated the same number of drywall layers, but shredded them more dramatically.
Back to 9mm, he tries out a hollowpoint 124-grain Remington Golden Saber Black Belt +P round (about 1400 fps). That bullet went through 17 layers of sheet rock, shredding their back surfaces similarly to the 223 bullet. Expansion of the hollow point was minimal, which is to be expected in a non-hydraulic medium (drywall instead of meat).
223 again: Hornady V-Max 55-grain bullet. Designed for varmints, the V-Max is meant to provide “rapid, explosive expansion” (2930 fps). This one made it through 13 layers of drywall before what was left of the bullet came to rest.
To top it off, he grabs a lever-action carbine and some CCI Mini-Mag 22LR ammo, with 40-grain round nose bullets (1220 fps). This one makes it through 11 layers. The same round fired from a semi-auto pistol with a 4" barrel (929 fps) made it through 10 layers — the equivalent of 5 household walls.
The moral of today’s video seems to be this: If you think your 9mm will go through significantly fewer walls than a 223, you’d probably be wrong. And the 22 can be a lot more effective than some folks would have you believe.
What results in reduced 9mm penetration with high velocity 9mm non-bonded rounds is that they fragment rather violently through intermediate barriers including drywall as being pushed at velocities beyond their designed limits so break into smaller pieces rather than staying intact.
BUT even then 9mm has MUCH less flash and blast out of 10-16" barrels than 5.56 out of the same -- meaning you can communicate and maintain much greater situational awareness.
Reasons for FN 5.7 include, but not an exhaustive list:
- intermediate barrier penetration more similar to 22lr than 5.56,
- ballistic performance similar to if not exceeding shorty 5.56 guns (since loads designed for shorter barrels),
- flash and blast similar to 9mm or .22 mag,
- pistol grip FN 5.7 "carbines" w/ 16" barrels meaning much more compact and better balance for single handle control than forward magwells,
- ability to run many rimfire suppressors, meaning less weight off the front-end to retain rear bias balance (so not necessarily needing support hand forward, and also a testament to reduced flash and blast relative to .223)
Negatives are obviously the cost of ammo and it being a somewhat unique and difficult to find caliber, limited weapon systems for it, and a somewhat unique or niche manual of arms across most available weapon systems.
But for older folks, women who also need to be corralling kids, etc., it's an extremely low recoiling, compact, and ballistically capable caliber at common civilian self defense distances that has a lot going for it, all things considered IMO.
YMMV.
