Terminal effectiveness from 7" AR - 5.56mm vs 9mm

[Barnacle Bill]

Eberlestock's S25 Cherry Bomb pack is designed to conceal a 7"-ish AR SBR or pistol in a non-tactical-looking pack. I'm thinking about something like this for an AR pistol with the SIG SB15 brace installed, for a car gun. The anticipated scenario is at worst a temporary local breakdown of law and order, not a long-term Mad Max scenario, so it would be highly unlikely to ever need to engage targets farther than 100 yards (probably a lot less).

Going in assumption would be I'd use the same "go to" load I already use in the caliber - MK 318 or Gold Dot 124gr +P, 5.56mm or 9mm respectively.

Which is going to work better from the terminal ballistics perspective from a 7"-ish barrel at ranges under 100 yards?

[MegademiC]

Shot to shot an AR pistol with the right load. I cant say about mk 18. That said, when you factor in everything else, I'd just stick with a pistol. Maybe put a real rifle in the trunk or under a seat. I definitely wouldn't want an AR pistol when the SHTF and I don't have ear pro. I would suggest a shotgun (with shot and slugs) or rifle, over it.

[Voodoo_Man]

Seeing as how pistol ammo is not as effective as rifle ammo (in this case 556) in stopping people, I'd go with the rifle ammo.

If you are looking for the "ultimate weapon for shtf" get something in the 12inch range, suppressed in 762.

[Barnacle Bill]

While clearly rifle ammo is more effective than 9mm from a 14.5" M4gery, I wasn't so confident about a 7" barrel. Hence the question.

PWS, who makes the SBR Eberlestock demos in their pack, claims muzzle velocity of 2368 fps (with unspecified ammo) and "lethal capability" out to 200m. I don't know at what velocity Mk 318 stops fragmenting, though, and I suppose .22LR (which I suppose any 5.56mm bullet acts like below its fragmentation or expansion velocity) still has "lethal capability".

I would still be carrying a pistol and it would be more accessible than something in a pack, but a 7" AR pistol fits in the pack assembled and nothing bigger does.

[TehLlama]

Running heavy ammunition with rifle quantities of power is still going to be more effective - the only way 9mm can catch up is finding a way to send 55gr or lighter projectiles in such a way that they don't change attitude in the first foot of terminal behavior (and thus never fragment or make a larger temporary cavity), and run a 9mm JHP projectile that does deform exactly as designed. Run any barrier blind load through the AR pistol and you're back to be miles ahead with the rifle cartridge - but nowhere near as practical as if running that same setup through a 10.3-12.5" barrel. If you're bringing the overhead size/weight of the AR receivers and receiver extensions, just run a proper length barrel anyway - the handgun absolutely has its place. Deploying from a pack is never very quick (still have to dig it out, sling it, probably charge it since I'm not wild about Condition 1 weapons in bags), so storing an SB-15 pistol or true SBR with an 11.5" or 10.5" barrel (probably using an RCS Top Cap) and having the lower stowed separately (with a couple magazines too) and the sling pre-attached is probably 3 seconds slower to deploy, but effective out to twice the distance (not to mention less ridiculous to fire indoors).

[Sixgun_Symphony]

Eberlestock's S25 Cherry Bomb pack is designed to conceal a 7"-ish AR SBR or pistol in a non-tactical-looking pack. I'm thinking about something like this for an AR pistol with the SIG SB15 brace installed, for a car gun. The anticipated scenario is at worst a temporary local breakdown of law and order, not a long-term Mad Max scenario, so it would be highly unlikely to ever need to engage targets farther than 100 yards (probably a lot less).

Going in assumption would be I'd use the same "go to" load I already use in the caliber - MK 318 or Gold Dot 124gr +P, 5.56mm or 9mm respectively.

Which is going to work better from the terminal ballistics perspective from a 7"-ish barrel at ranges under 100 yards?

Not MK318 but 55gr Gold Dot (with a respectfully low expansion threshold)...its not true ballistics gel but the results are interesting http://www.youtube.com/watch?v=yXFfxMjyZ4c

[lunchbox]

Not MK318 but 55gr Gold Dot (with a respectfully low expansion threshold)...its not true ballistics gel but the results are interesting http://www.youtube.com/watch?v=yXFfxMjyZ4c

That looks interesting.

[FloridaWoodsman]

Just a couple of thoughts...
If I were a hundred yards from danger, I would be thinking more in terms of a different direction than in engaging, so I would stick with a pistol.
Be sure to check your local laws as to just what is legally concealable.

[Barnacle Bill]

If I were a hundred yards from danger, I would be thinking more in terms of a different direction than in engaging, so I would stick with a pistol.

As I wrote, "highly unlikely to ever need to engage targets farther than 100 yards (probably a lot less)". However, beyond bad breath distance a carbine is going to have advantages over a conventional pistol, and an AR pistol with the SIG SB15 brace installed - while legally a pistol - is effectively a SBR carbine without NFA entanglements. At least until ATF changes its mind, which wouldn't surprise me.

Be sure to check your local laws as to just what is legally concealable.

Apparently a pistol is a pistol. An actual SBR would be legal, too, as long as there isn't a loaded mag in the mag well. Well, technically I think you'd need to put the mag(s) in a different pocket of the pack than the SBR, but mounting the sort of mag pouch that fully encloses the mags to the internal molle in the pack would satisfy that.

[FloridaWoodsman]

You might find this experiment with 9mm interesting
https://www.youtube.com/watch?v=_wXFf34bB34