Relevance of pistol caliber carbines

SmElly

Regular Member
Bear with me guys, I'm just some guy on the internet trying to learn more about martial force. So, I'm going to throw out some statements in search for input from folks that know more than I do.

1. The only hits that matter at close distance are heart and head (right?)
A lung or gut shot at CQB distance doesnt mean sh*t (right?). If I havent stopped the bad guy's trigger finger from working, I havent eliminated the threat (see modcast clip 16-1)

2. A heart/frontal cortex shot from a pistol round is just as good as a heart/frontal cortex shot from a rifle round (right?). A hole is a hole is a hole (right?). The threat is dead as dead can be?

3.If point 1 and 2 are correct, wouldnt a pistol caliber long gun be more optimal than a rifle? (lower recoil, meaning faster opportunities to drive holes through the heart/brain?)

Help me out here , I'm looking for criticisms.
 

ammomfg

Newbie
Going between a carbine (lets just say AR-15) and a PCC (pistol caliber carbine) there's a massive step down in energy, energy is what kills. That said, there's a threshold at which all energy just makes you dead, assuming something (or someone) can't actually be more dead than dead.

There are a number of rabbit holes you can go down with this line of thinking, however I don't think there are appreciably specific differences between a PCC and an AR-15 when it comes to making people at close range dead. What would be the deciding factor for me: Reliability. I've owned a few 9mm AR conversions and all of them sucked, they had feeding issues, and cycling issues, and just generally were a lot of suck. Also, while you may get a bit more velocity going from a handgun to a PCC, it doesn't even compare when going from a handgun to a rifle caliber carbine.

The limitation on using a long gun to defend yourself in your house, is how easy can you move it around, in this case, I would probably just drop the PCC and not look back. Now if you start comparing some of the modern options, say an AR-15 pistol (chambered in 5.56) with a *ahem* brace, vs say a CZ scorpion with an *ahem* pistol brace, I think you're starting to get into the territory of the PCC making more sense and I would probably agree.

For whatever reason triads are an important concept, and plenty of good jokes have been made from them. For any "defensive" gun the triad is basically: Reliability, Lethality, Accuracy. There are other factors that may play in: noise signature, over-all length but that's about it. And as with all triad concepts, pick two. In this case, my two choices are always going to be Reliability and Lethality. Shotguns aren't the most accurate, but they'll own anything inside 25 yards, even with bird shot, and with a bit of practice they're damn reliable, and overwhelmingly lethal. (please don't use bird-shot for defensive purposes)

In all, use whatever you're comfortable with, however don't be comfortable with anything unreliable, because of the reliability aspect, a PCC is not my first choice.
 

Sunshine_Shooter

Established
they'll own anything inside 25 yards, even with bird shot, and with a bit of practice they're damn reliable, and overwhelmingly lethal. (please don't use bird-shot for defensive purposes)

You scared me there for a second!

In all seriousness, why do you have "accuracy" as a defensive gun triad? Are you meaning for all defensive guns, not just in-home defense?
 

SmElly

Regular Member
Service caliber pistol rounds poke holes. Service caliber rifle rounds poke holes and a lot more. 5.56 is a pretty easy shooting carbine as it is too.
Going between a carbine (lets just say AR-15) and a PCC (pistol caliber carbine) there's a massive step down in energy, energy is what kills. That said, there's a threshold at which all energy just makes you dead, assuming something (or someone) can't actually be more dead than dead.

There are a number of rabbit holes you can go down with this line of thinking, however I don't think there are appreciably specific differences between a PCC and an AR-15 when it comes to making people at close range dead. What would be the deciding factor for me: Reliability. I've owned a few 9mm AR conversions and all of them sucked, they had feeding issues, and cycling issues, and just generally were a lot of suck. Also, while you may get a bit more velocity going from a handgun to a PCC, it doesn't even compare when going from a handgun to a rifle caliber carbine.

The limitation on using a long gun to defend yourself in your house, is how easy can you move it around, in this case, I would probably just drop the PCC and not look back. Now if you start comparing some of the modern options, say an AR-15 pistol (chambered in 5.56) with a *ahem* brace, vs say a CZ scorpion with an *ahem* pistol brace, I think you're starting to get into the territory of the PCC making more sense and I would probably agree.

For whatever reason triads are an important concept, and plenty of good jokes have been made from them. For any "defensive" gun the triad is basically: Reliability, Lethality, Accuracy. There are other factors that may play in: noise signature, over-all length but that's about it. And as with all triad concepts, pick two. In this case, my two choices are always going to be Reliability and Lethality. Shotguns aren't the most accurate, but they'll own anything inside 25 yards, even with bird shot, and with a bit of practice they're damn reliable, and overwhelmingly lethal. (please don't use bird-shot for defensive purposes)

In all, use whatever you're comfortable with, however don't be comfortable with anything unreliable, because of the reliability aspect, a PCC is not my first choice.

Thank you for the responses. I have no intention of ditching my AR in favor of a PCC. Just doing my best to grapple with different lines of thinking.

PCC's are great for small women and weak or disabled men.
Indeed.
 

Dpvaz56

Member
If wanting all the shortness in a firearm is a consideration to go PCC you then fall into 300BLK territory. Rifle caliber is the way to go unless you're doing it for competition, a fun-gun, or for small women and weak men (to quote Mr. McQueen)
 

SmElly

Regular Member
Going between a carbine (lets just say AR-15) and a PCC (pistol caliber carbine) there's a massive step down in energy, energy is what kills.
If we wanted to take the conversation further, I'd say I disagree with this statement (in a way). I'd make the argument that energy on its own isnt an effective wounding mechanism.

Most 9mm loads deliver less than 400 lbs. of muzzle energy, whereas some fighters' punching power has been clocked at over 1000 ft/lbs.
As we know, the difference here is penetration.


If wanting all the shortness in a firearm is a consideration to go PCC you then fall into 300BLK territory. Rifle caliber is the way to go unless you're doing it for competition, a fun-gun, or for small women and weak men (to quote Mr. McQueen)
Nah, I was mostly looking at this from a follow up shot perspective.
 

Chaucer

Amateur
I owned a scorpion (6.5 inch barrel version) and an AR 5.56 pistol (11.5"). I ran them back to back to try and work out this same issue.

There was subtle differences back and forth, but the conclusion I came to was that the only way the Scorpion made sense was in the smallest reliable configuration. The new Micro-K scorpion, for example. I could clear a house so smoothly with that little guy, and 32rds, ergonomic red dot and light mounting with shouldered firing would be a significant step up from my handgun+light while making pieing doorways a breezs.

But if the PC is pushing the size of an AR, then you get very little returns. The Micro-K really comes into its own if you want to run a suppressor, which would turn an SBR into a full-length carbine.
5b57965c993e4eeecc826bfe311fcec2.jpg


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Low_Speed_Notper8or

Regular Member
Really the only thing I think a PCC might make sense is if your going on something like a sub 10" barrel maybe having something like a hot 10mm or .357 would be the ticket since your getting about as much muzzle energy(750-1000 Ft-Ibs) as a intermediate round but with less muzzle blast, and you have a bigger bullet. (Also this was the thinking for subsonic bullets with the Russian 9x39mm). However 9mm Luger in a longer barrel really doesnt gain much energy and I agree 9mm PCCs are kinda pointless

And if you couple a more "magnum" pistol round with an expanding bullet you might really have something. Kinda similar to what Randy/Jordan talked about as a PDW on the "improving the AR" modcast.

As much as I would love to see a 10mm or 7.5FK or some rimless .357 in a PCC and its a cool concept that deserves further development, right now there is no good platform that has really seen alot of development and is reliable. There is a reason why when I was in college I kept a mossberg 500 with #4 buck as my home defense gun, then a polish AK and now a BCM AR, it just works.

The question I would like to pose is though with a 16" non NFA AR shooting 55 grain ammo really is there any more recoil then shooting a pistol caliber round, especially with modern muzzle brakes? And with 6-7 pound guns really are you losing much weight
 

Chaucer

Amateur
^^^ To be clear, I am speaking towards speed, efficiency and handling characterisitcs. I think caliber comparison is pretty black and white. I was interested if these factors could possibly outweigh the lethality benefits.

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SmElly

Regular Member
^^^ To be clear, I am speaking towards speed, efficiency and handling characterisitcs. I think caliber comparison is pretty black and white. I was interested if these factors could possibly outweigh the lethality benefits.

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I gotcha. Thanks for sharing your experience. Interesting stuff.
 

JLL2013

Regular Member
The benefits of the PCC are solely weight, reduced recoil, and noise reduction. Its up to everyone to decide for themselves if those outweigh the external, terminal, and wound ballistic penalties.
 

Low_Speed_Notper8or

Regular Member
I owned a scorpion (6.5 inch barrel version) and an AR 5.56 pistol (11.5"). I ran them back to back to try and work out this same issue.

There was subtle differences back and forth, but the conclusion I came to was that the only way the Scorpion made sense was in the smallest reliable configuration. The new Micro-K scorpion, for example. I could clear a house so smoothly with that little guy, and 32rds, ergonomic red dot and light mounting with shouldered firing would be a significant step up from my handgun+light while making pieing doorways a breezs.

But if the PC is pushing the size of an AR, then you get very little returns. The Micro-K really comes into its own if you want to run a suppressor, which would turn an SBR into a full-length carbine.
5b57965c993e4eeecc826bfe311fcec2.jpg


Sent from my SAMSUNG-SM-N920A using Tapatalk

^^^ To be clear, I am speaking towards speed, efficiency and handling characterisitcs. I think caliber comparison is pretty black and white. I was interested if these factors could possibly outweigh the lethality benefits.

Sent from my SAMSUNG-SM-N920A using Tapatalk

IDK, being the kind of guy I am, I see something like that and I wonder if a hotter round and bullpup configuration would be a more optimal solution. And one that would not give up that much lethality

For exampe, the FK Brno Field pistol with its 7.5mm round is pushing a 100ish grain bullet at 2000fps for 880 Ft-ibs in a 6 inch barrel. You extend that barrel to 8-10 inches in a bullpup like I talked about and I'm sure you can push to over 1000-Ibs and get that velocity up and now you are in the realm of .300 blackout velocity and 5.45 muzzle energy.

If you get all of the benefits like you talked above of a super short weapon and have .223 Remington/5.45 levels of energy(enough with good bullet design to be pretty lethal) you really would have quite a great weapon. The problem like I talked about above is a lack of good platforms that have had enough R&D and testing to be reliable and also enough government adoption to bring cost of production down to something decent.
 

Yondering

Regular Member
2. A heart/frontal cortex shot from a pistol round is just as good as a heart/frontal cortex shot from a rifle round (right?). A hole is a hole is a hole (right?). The threat is dead as dead can be?

I think most of this has been covered already, but I'd like to address #2, specifically the "a hole is a hole" part.

In short, no it is not. That's a common argument made on gun forums, but it ignores the size of the hole, i.e. peripheral damage beyond the diameter of the bullet. Pistol caliber rounds can and do cause some peripheral damage (contrary to what some insist), but high velocity rifle rounds generally cause a lot more, with few exceptions.

This matters when we consider hits to the body that are not direct hits to vital areas but somewhat close. As just a crude example - imagine a shot that misses the spine by 2" to the side. Do you want that bullet to make a caliber size hole, or a grapefruit size hole? Which one will still destroy the vitals and shut down the nervous system? That may seem like an extreme example, but I've seen both conditions on game animals with dramatic differences. Even beyond the peripheral damage, the shock produced by a high velocity rifle round can shut down the nervous system.

Also, while a heart shot is almost certainly fatal, don't count on it for an immediate shutdown like a shot to the nervous system; a lot can happen between a heart shot and collapse. In hunting it's really common for heart shot animals to run a hundred yards or more before collapsing, or sometimes stand there for a bit like they haven't been hit. Yeah, animals are different than people, but I think some of the same principles still apply.
 

Low_Speed_Notper8or

Regular Member
Having just listened to the Ballistics modcast again I'm looking forward to his input...
Same, and also im also curious to see some data (especially real world) on medium velocity rounds (1250-2000fps) with expanding bullets like .300 blk in a short barrel or a .357 or 44 in a longer barrel or .30 carbine with a modern bullet.
 

Grizzly

Regular Member
If the goal is to get good hits as fast as possible while keeping good ballistic performance I'd venture the answer is no. To address your questions:

1. Sure a lung shot when they are hands on isn't ideal.
2. No a hole isn't a hole. If that was the case FMJ from a .380 pistol would be the same as a 300 winmag. Expansion and using the energy of the round to push a fully expanded projectile to proper penetration matter.
3. One and two aren't true.

Also, have you compared your splits on a timer between accurate fire with a 5.56/300blk carbine and accurate fire with a 9mm or .45acp carbine at close range? I bet they won't be that different. Now stretch that to distance and I bet the rifle calibers really shine. You keep more velocity and less mental math for bullet drop. So you are giving up a big advantage for little or no gain.

If you are using Reston's story as an example for picking a weapon you might as well argue that having a bayonet is a big plus. If Jared could have shoved 12" of steel into the bad guy's eye socket it might have ended sooner....
 

Bub

Amateur
What the guy said above, a PCC is great for fun and competition. I have a AR stylish 9mm setup for USPSA and Steel Challenge and it works great for that. It's also handy for shooting steel targets up close. As to the recoil I personally don't think it is that much less than a 5.56 to make a difference for most people. Also, most of those little PCCs weight about what some ARs do so I don't see that as a real benefit either. I really think a shotgun or 5.56 carbine would be a better option. It is 2018 after all. For someone with recoil and weight issues, who doesn't want to use a .22lr, maybe something like the FN PS90 would be worth looking at. I don't know anything about the PS90 other than what I have read so take it for what it's worth. I haven't heard too great of things about terminal performance from the 5.7x28 round (mainly just pokes holes).
 
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