AR Pistol Use Case
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Tommygunn
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.300 AAC Blackout was developed by necking up the 5.56mm. round and using a different powder. In a pistol it maintains a better percentage of its muzzle velocity/power at distance than its parent. Also, it can use the same magazines as the 5.56mm. A lot (but not all) parts are common to both, although this is dependant on maker. My Sig Canebrake for example has no buffer tube, the recoil springs are dual springs atop the bcg, and the carrier is an abbreviated version of the AR-15 version. The bolt looks the same but isn't; the lugs are radiused in between them.
That makes them stronger.
It also means only Sig Sauer will make replacement parts.
...And, of course, there's the .30 caliber bullet the Blackout uses versus the .223 round the regular AR-15s use as well.
But they make AR RIFLES in .300 BLK too, so it doesn't have to be a pistol, you know!
I'll give you the best reason of all- because you won't know for certain until you get one and shoot it for yourself.
Note the energies out of 10" barrels. The 110gr .300 out of the 10" barrel has as much energy as the 5.56 55gr out of a 16" barrel.
RavenTai
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5.56/223 is a very light weight small diameter bullet, velocity and the energy velocuty creates is a huge part of its terminal ballistics, 5.56 the powders and max pressures allowed require a long barrel to be effective, 16" is notable less effective than 20", go below 16" and it is still deadly but significantly less so than rifle length barrels, the jiant fireball of your 7" 223 is energy lost, not sunk into the projectile.
300blk is better tuned to get energy out of a short barrel.
Personally I won't own a 300blk, loaded mags, look similar, will fit in a .223 gun, will chamber and take a firing pin hit, but the bullet will not fit down the bore, chamber pressure will skyrocket until the gun explodes. With 3.5 shooters in my home and growing some without the required knowledge, I can't do it personally.
Tommygunn
Member
I don't blame you in your position. I am very careful to keep the 5.56 stuff separate from the Blackout. I even bought some Magpul magazines marked ".300 Blackout" to help .... even though regular 5.56 mags work. Still, the only real safety is the gray mush between the ears!
RavenTai
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I don't blame you in your position. I am very careful to keep the 5.56 stuff separate from the Blackout. I even bought some Magpul magazines marked ".300 Blackout" to help .... even though regular 5.56 mags work. Still, the only real safety is the gray mush between the ears!
If it were just me maybe, I would agree that your brain could be leveraged to work against the risk, I would have to be constantly aware and careful.
but what about less passionate and technical shooters? my wife is trained on one of our AR's for home defence, she paid attention and leaned how to load, fire and make safe, reload etc, she has seen it enough to not try to stuff an FAL mag or AK mag into an AR, even if she tried it won't fit.
But could I train her to that level where she would not pick up a virtually identical 300blk mag in the dark as she was trying to gather the kids? Or my son to notice a stray 300 as he is loading mags at the range?
When my son started shooting I sold my 8mm mauser (vz-24) and al the ammo for the same reason, 8mm will chamber in 30-06 and ignite, but not fit down a 30 cal bore, I wasent about to let go of my M1 Garand and several bolts. Although I do have to keep the 30-06 away from the m1, worst case is a bent op rod, and loading clips that fit nothing else with m2ball is a good choke point.
mcb
Member
The danger is real but its not quit that bad. Most 300 BO ammo will not chamber in a 556 gun. The bullet must have enough room to set back into the case far enough to allow the bolt to lock into battery. Certainly possible but its not going to happen every time and with some ammo it's basically impossible. ie I gaurenteed my 300 BO hunting load would never chamber in a 556 gun the blunt copper bullet is sitting almost right on top of the powder charge and cannot be pushed back into the case far enough to chamber no matter how hard you try. Again there is a very real danger of accidentally chambering a 300 BO in a 556 chamber and it going boom but it is not a 100 % guarantee that if you mix it up its going to give you a kaboom.
Keep them marked and separated and educate those around you about the danger. Awareness is key.
Personally if I was going to get rid of one or the other it would be 556. I find 300 BO more fun and more useful.
Keep them marked and separated and educate those around you about the danger. Awareness is key.
Personally if I was going to get rid of one or the other it would be 556. I find 300 BO more fun and more useful.
As many others have noted, 5.56 in short barrel= less energy + more muzzle blast and noise. Rifle or carbine does it better. 300 blackout with 10" barrel= what the cartridge was designed for, good muffler function, and better thump in a compact package. Mine is a $300 PSA kit, works fine and no regrets.
I do use Magpul mags designed for 300, painted and banded accordingly, with an upper marked on bolt cover and forend. I also plan to put witness marks on mag and magwell to further confirm 300 only in 300 gun. >|<
I do use Magpul mags designed for 300, painted and banded accordingly, with an upper marked on bolt cover and forend. I also plan to put witness marks on mag and magwell to further confirm 300 only in 300 gun. >|<
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herrwalther
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Comparing a 5.56 to a 9mm is nowhere near the same in regards to ballistics. In a 10" barrel, common 5.56 ammo will be going at least 1000 FPS faster than a comparable 9mm bullet. There are advantages to a PCC AR, ballistics is not one of them. Not by a long shot.
http://ballisticsbytheinch.com/9luger.html
http://www.ballisticsbytheinch.com/223rifle.html
I have a 16" AR. Plan to build an AR pistol in 5.56. On a budget it makes more sense to have an AR pistol in 5.56 to simplify ammo stocks, magazines etc instead of going 9mm PCC or even 300 BLK.
http://ballisticsbytheinch.com/9luger.html
http://www.ballisticsbytheinch.com/223rifle.html
I have a 16" AR. Plan to build an AR pistol in 5.56. On a budget it makes more sense to have an AR pistol in 5.56 to simplify ammo stocks, magazines etc instead of going 9mm PCC or even 300 BLK.
Tommygunn
Member
First, I am in NO WAY attempting to argue you into agreeing with, or doing anything, your conscience and your own good sense tell you you should not do. I think that many people who own guns in similar calibers can face the potential problem of using, or trying to, the wrong caliber ammo in a particular gun chambered in a similar caliber.
I have several lever action rifles, a .22LR, a .30-30, a .32-20, two in .45 Colt, and one in .44 Magnum and two others in .44-40. The .44 magnum round is very similar in size to the .44-40. When I acquired the .44 magnum I became aware of the potential of chambering the wrong cartridge in one or the other rifles. I carefully checked and found out, due to minor dimensional differences, that neither caliber would chamber correctly in the other rifle. Still, to this day, even knowing the above, I remain very careful to KNOW what caliber I'm actually using BEFORE I blindly go off and try to use the wrong ammo.
I have two .308 rifles and one .30-'06, and again, here, I am also very careful with the ammo.
Again, your guns, your family, your responsibility: your choice. Not mine.
To me one of the biggest pros of an ar pistol (I ha e 2 300 aac blackouts with 10.5” barrels) is the ability to maneuver and deploy from within a vehicle. From a seated position I can more easily access and more speedily fire my home brew blackout than my belt carry ccw... and the 300 is a big leap forward in power over 9mm. ... which also would be my answer to the OPs question of a PCC; PCCs are more controllable than a pistol but don’t give much more power. I would only recommend them for target sports and to a few especially recoil sensitive individuals.
To answer the OP,
frankly, being proficient with a pistol takes a lot of practice, and is a perishable skill. it's much more intuitive to point when using two hands spaced apart like a carbine or rifle. you've also got a bit more leverage. and when firing rapidly, you'll see many pistols rock 15-45* up, which you simply don't see with carbines chambered in the cartridges under discussion here.
it wouldn't surprise me if most USPSA competitors are a wee bit faster putting multiple rounds on multiple targets than they are with a pcc, but any n00b can do pretty good with a pcc, and competent people can focus less and still perform reasonably well with a pcc.
in other words, they're just much easier to shoot.
given ease of shooting, our legal constraints seem to favor firearms that identify as "pistols" for reasons stated above
the choice of cartridge comes next:
most military 556 ammo was designed to fragment, instead of expand. the results out of rifles, where velocity is high, is very impressive. when velocity drops below the point that bullets will reliably fragment, they just poke .22 holes in things. that velocity is usually in the 2600 range for m193.
observe:
that means the effective range out of a short barrel is going to be well under 150 yards. beyond that... you may as well be stabbing them with a long distance ice pick. it's just suboptimal for "stopping". as your barrel gets shorter, terminal ballistics gets worse, reliability gets worse, noise goes way way up, etc because port and muzzle pressure is much much higher.
Now of course, you could switch to expanding bullets, but expanding bullets don't make as big a mess as a properly fragmenting one does, imho. i think a lot of LEO ammo these days is expanding, fwiw.
but most people think a better idea is to switch to 300blk. it's not because of the energy calculation. heck, a significant portion of 300blk users are shooting subsonic. it's because those bullets are designed to rapidly expand at subsonic velocities. this is the one I use https://www.lehighdefense.com/index.php?_route_=all/308-maximum-expansion-194gr-subsonic-bullet they, like pistols, deliver a lot of mass on target at relatively low velocities. and they sound great suppressed. but they are much more aerodynamic like rifle bullets, compared to pistol bullets, so they are easier to shoot at distances out to say, 400 yards than short stubby pistol bullets.
or you can just go with a pistol caliber like 9mm or 45acp. the advantages are low cost (typically less than half the cost) and low recoil which means if you're primarily concerned with plinking, especially shooting fast on multiple steel targets at close range, this is an obvious choice. but from a terminal ballistics standpoint, it's just not in the same league as rifle rounds. plan on shooting something several times.
one downside is weight. 3 mags full of subsonic pistol or 300blk weighs noticeably more than 55g 223.
if you pick 223/556 or 300blk, an AR pistol is the obvious choice because both rounds were designed to be shot in that firearm and those magazines.
if you pick 9mm, then it's a more difficult choice of an AR pistol or something that looks like an MP5
I chose a cz scorpion micro and put a silencerco osprey suppressor on it. it's a LOT of fun to shoot. but ultimately my choice came down to the fact that i plan to use it mostly at night, with NV at laser ranges. and i want it compact. the AR15 9mm are all proprietary and i'm not sure how well parts interchange, and there are a LOT of vendors, so i don't know which one is eventually going to become a standard. so i figured i'd go with something designed from ground up to shoot 9mm instead of shoehorning it into something made to shoot 556. however, familiarity with basic operations was a consideration as well (i.e. where the bolt release, magazine release, etc are
one downside to the whole PCC, is that they're obviously meant to be full auto and we are obviously not allowed to have them unless you find a registered AR lower, or decide to spend $30k on an HK trigger pack. it's unfortunate that there wasn't a pistol bump stock for 9mm before they were banned.
this is important to sort out, for sure. but i think it's fairly easy. color code them. put fluorescent paint outside the magwell and on the mags that have 300blk or something similar to distinguish them.
frankly, being proficient with a pistol takes a lot of practice, and is a perishable skill. it's much more intuitive to point when using two hands spaced apart like a carbine or rifle. you've also got a bit more leverage. and when firing rapidly, you'll see many pistols rock 15-45* up, which you simply don't see with carbines chambered in the cartridges under discussion here.
it wouldn't surprise me if most USPSA competitors are a wee bit faster putting multiple rounds on multiple targets than they are with a pcc, but any n00b can do pretty good with a pcc, and competent people can focus less and still perform reasonably well with a pcc.
in other words, they're just much easier to shoot.
given ease of shooting, our legal constraints seem to favor firearms that identify as "pistols" for reasons stated above
the choice of cartridge comes next:
most military 556 ammo was designed to fragment, instead of expand. the results out of rifles, where velocity is high, is very impressive. when velocity drops below the point that bullets will reliably fragment, they just poke .22 holes in things. that velocity is usually in the 2600 range for m193.
observe:
that means the effective range out of a short barrel is going to be well under 150 yards. beyond that... you may as well be stabbing them with a long distance ice pick. it's just suboptimal for "stopping". as your barrel gets shorter, terminal ballistics gets worse, reliability gets worse, noise goes way way up, etc because port and muzzle pressure is much much higher.
Now of course, you could switch to expanding bullets, but expanding bullets don't make as big a mess as a properly fragmenting one does, imho. i think a lot of LEO ammo these days is expanding, fwiw.
but most people think a better idea is to switch to 300blk. it's not because of the energy calculation. heck, a significant portion of 300blk users are shooting subsonic. it's because those bullets are designed to rapidly expand at subsonic velocities. this is the one I use https://www.lehighdefense.com/index.php?_route_=all/308-maximum-expansion-194gr-subsonic-bullet they, like pistols, deliver a lot of mass on target at relatively low velocities. and they sound great suppressed. but they are much more aerodynamic like rifle bullets, compared to pistol bullets, so they are easier to shoot at distances out to say, 400 yards than short stubby pistol bullets.
or you can just go with a pistol caliber like 9mm or 45acp. the advantages are low cost (typically less than half the cost) and low recoil which means if you're primarily concerned with plinking, especially shooting fast on multiple steel targets at close range, this is an obvious choice. but from a terminal ballistics standpoint, it's just not in the same league as rifle rounds. plan on shooting something several times.
one downside is weight. 3 mags full of subsonic pistol or 300blk weighs noticeably more than 55g 223.
if you pick 223/556 or 300blk, an AR pistol is the obvious choice because both rounds were designed to be shot in that firearm and those magazines.
if you pick 9mm, then it's a more difficult choice of an AR pistol or something that looks like an MP5
I chose a cz scorpion micro and put a silencerco osprey suppressor on it. it's a LOT of fun to shoot. but ultimately my choice came down to the fact that i plan to use it mostly at night, with NV at laser ranges. and i want it compact. the AR15 9mm are all proprietary and i'm not sure how well parts interchange, and there are a LOT of vendors, so i don't know which one is eventually going to become a standard. so i figured i'd go with something designed from ground up to shoot 9mm instead of shoehorning it into something made to shoot 556. however, familiarity with basic operations was a consideration as well (i.e. where the bolt release, magazine release, etc are
one downside to the whole PCC, is that they're obviously meant to be full auto and we are obviously not allowed to have them unless you find a registered AR lower, or decide to spend $30k on an HK trigger pack. it's unfortunate that there wasn't a pistol bump stock for 9mm before they were banned.
this is important to sort out, for sure. but i think it's fairly easy. color code them. put fluorescent paint outside the magwell and on the mags that have 300blk or something similar to distinguish them.
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