5.7 in Home Defense

[m4brian]

I am asking this in the urban/suburban context and NOT in an 'all terrain' solution. Home defense. Room to room, maybe a shot in the yard, etc.

I used to rely on having an AK handy, which I still might, but given the penetration and ensuing legal problems of hitting someone 'down the street', have moved to a PCC with 8" barrel in 9mm. I also have noticed that getting a head shot at 25+ yards is now trivial and that is NOT true with a handgun. So... its better and safer to use the PCC.

But, as 5.7 gets near $30/box and maybe that improves, and it shoots flatter at longer range, is there some point where a PCC in 5.7 becomes a better choice especially with near zero recoil, and lesser strength folks in the household can charge the weapon easier and hit a tad better?

Just asking. The latest thread (I could find) was a 5.7/5.56 deal and that's not in view, nor should it be. (I don't even understand a comparison to the 5.56 - its not close).

I get the McNamara (you need to shoot a ton to be good) deal, but I find that to be not as active with a shoulder fired PCC and a dot. Pat is referring to the 'fighting carbine scenario' I assume in that context.

[titsonritz]

A couple threads that may be of interest.

Small Caliber PDW's: FN 5.7 mm/HK 4.6 mm

The Presumptive Hazards of Over-Penetration

[Todd.K]

Over penetration concerns are vastly overstated in my opinion.

Shoulder fired with a dot does take less practice to maintain a reasonable proficiency than a pistol.

I believe there are several agency/depts that actually used 5.7 in an OIS and they no longer use it. I would rather have 9mm.

Better reliably than .22 or anything rimfire for the recoil/charging challenged.

[m4brian]

My "over penetration" concern has nothing to do with a hit, but a miss as stated. If I HIT with a X39, I know I am better off and the subsequent 'over-pen' is not the issue. I am concerned with the miss. The x39 scenario in this regard is nearly unacceptable. Thus the move to 9mm.

The current problem is that for my better half, charging the weapon in various circumstances is tough with a blow back (9mm) system. I was thinking the 5.7 is not, AND you gain lower recoil in a light weapon.

Then it is down to lethality on a non-armored perp out to 20 yards. 9mm is better?

[Todd.K]

Police departments almost entirely replaced shotguns with 5.56 patrol rifles a decade or two ago. I’m not aware of any change in the likelihood of distant bystanders being hit. At normal angles the 9mm is just as likely to hit something a house away, and more likely to ricochet back up when it hits the ground.

5.7 terminal performance is dismal. I do consider it a reliability upgrade over rimfire. The 5.7 only existed to defeat soft body armor, and quickly became obsolete as plate armor became common. But, a gun she is comfortable using is better than one she is not comfortable with or no gun at all.

Have you considered a forward side charging 9mm? Is yours an AR pattern 9mm? If so make sure it doesn’t have an AR-10 recoil spring, I’m don’t know why someone thought that up but it’s terrible.

[tkoglman]

Why not just use a 5.56mm? A lot cheaper ammo than 5.7 and more choices in weapons. I had the opportunity to test bullet penetration in actual houses. The USMC bought up a couple small streets of houses to expand the training area by Camp Lejeune. We shot from inside and outside with every small arms ammo the Marines had at the time: 9mm, .45, 5.56, 7.62, and 12ga. The 5.56mm had the least penetration.

[B Cart]

A couple threads that may be of interest.

Small Caliber PDW's: FN 5.7 mm/HK 4.6 mm

Great article with good real-life data. A full-auto P90 is one of the funnest guns i've shot, but that round sucks at killing things.

To the OP, i'd stick with your PCC in 9mm with high quality ammo over 5.7. I have multiple 9mm PCCs and they are a blast to shoot, and i'd feel confident engaging a threat with mine if I had to.

THAT BEING SAID, if you're open to ideas, i think 300BLK is a much better option for a small PDW, and they are very manageable to shoot and operate. Probably going to have less potential penetration than 7.62x39 as well. I run an 8" suppressed 300BLK with Barnes 110gr Tac-TX ammo for my HD gun, and my wife and i both shoot it really well. That would be my first choice. But if you don't want a rifle caliber, 9mm is probably a better choice over 5.7

[WillBrink]

Why not just use a 5.56mm? A lot cheaper ammo than 5.7 and more choices in weapons. I had the opportunity to test bullet penetration in actual houses. The USMC bought up a couple small streets of houses to expand the training area by Camp Lejeune. We shot from inside and outside with every small arms ammo the Marines had at the time: 9mm, .45, 5.56, 7.62, and 12ga. The 5.56mm had the least penetration.

That has been shown time and time again, yet people either unawares, or cognitive dissonance related.

[Clint]

Todd already touched on it, but a properly configured 9mm AR shouldn't be any harder to charge than a 556 AR.

The current problem is that for my better half, charging the weapon in various circumstances is tough with a blow back (9mm) system. I was thinking the 5.7 is not, AND you gain lower recoil in a light weapon.

Then it is down to lethality on a non-armored perp out to 20 yards. 9mm is better?

[Ron3]

I use a Beretta CX4 9mm.

They are about $600 last I checked. Very reliable, use M92 pistol mags. Factory 30's about $25 when on sale.

You can move the charging handle to either side or do like I did and buy another handle so there is one on either side.

I have a RDS, light, and green laser on it. Underwood 68 gr +p LeHigh bullets register about 2100 fps over my chrono.

Light, low recoil, cheap, reliable, can mount what you need, cheap & plentiful quality mags, easy to hold with one hand if necessary. It's also fun.

5.7 was proven to stink in real-world use. Even in full auto by skilled users. No better than 9mm and possibly worse. Consider it a centerfire .22 magnum.