I live in the meth capital of the world and have already had a problem with a meth lab in my fairly nice complex (he was an employee of the complex and his meth lab blew up and the fire dept destroyed my apartment putting out the fire).  

I'm building a Commando replica and due to it's small size I'm considering using this rifle, equpped with an EOTech or AimPoint, as my home defense gun.  It would be replacing a Glock 19 with Speer 124 GR +P Gold Dots in that role.

I live in an apartment so penetration is a definate concern and I'm only concerned with fragmentation and/or expansion within about 20 yards.  I'll probably buy a 1/7" inch barrel but don't know if it would make a difference at such short range.

Any suggestions on ammo appropriate for this situation?  I've read the ammo FAQ still have this question.

Thanks in advance for any suggestions.

Have you considered using the slipover FH for the 16" bbl?
This was a pretty good thread on using the 11.5"
www.ar15.com/forums/topic.html?b=3&f=118&t=188018

20 yards? You probably want to go with as light as you can go, ammo-wise...40 grain TAP ammo, perhaps.

From Bushmaster concerning Hornandy TAP ammo:

40 grain TAP, Polymer tipped spitzer boat tail, part #83256, ballistic coefficient =.200: This bullet offers high velocity even in shorter barreled weapons with reliable functioning in the AR15 weapon system. It also offers rapid expansion, high fragmentation and little retained weight. This round is intended primarily for situations where its' limited penetration, extreme fragmentation and reduced ricochet potential are desired.

Quoted: 20 yards? You probably want to go with as light as you can go, ammo-wise...40 grain TAP ammo, perhaps. From Bushmaster concerning Hornandy TAP ammo: 40 grain TAP, Polymer tipped spitzer boat tail, part #83256, ballistic coefficient =.200: This bullet offers high velocity even in shorter barreled weapons with reliable functioning in the AR15 weapon system. It also offers rapid expansion, high fragmentation and little retained weight. This round is intended primarily for situations where its' limited penetration, extreme fragmentation and reduced ricochet potential are desired.

40 grain anything is a VERY bad idea from 11.5.  It's a bad idea from 20" too, frankly, if you are considering bipedal targets.

Evil_Ed: To understand this start with the Ammo-Oracle's note on:  Q. So which ammo is better, M193 or M855?  And what is all this discussion about fragmentation?  Are these dum-dum bullets?

Any TAP under 75 grain is an underperformer for self-defense, unfortunately.  Penetration doesn't make the critical 12" requirement.

corwin1968:  I would suggest 68 grain OTM, or perhaps 69 grain OTM Sierra Match King.  These are lighter than, say, 75 or 77 grain rounds, and will penetrate through walls and such less as a result.  They will still approach the 12" mark for penetration and tend to fragment down to lower velocities.  I doubt that you are, however, even going to get fragmentation out of them from an 11.5"

Depending on the construction of the walls where you are you might want to move up to 75 grain or 77 Grain Nosler (but not SMK).  I would actually suggest the 77 Grain NATO Nosler loading from Black Hills (since the extra velocity is going to be really important from an 11.5"er.

Quoted: Quoted: 20 yards? You probably want to go with as light as you can go, ammo-wise...40 grain TAP ammo, perhaps. From Bushmaster concerning Hornandy TAP ammo: 40 grain TAP, Polymer tipped spitzer boat tail, part #83256, ballistic coefficient =.200: This bullet offers high velocity even in shorter barreled weapons with reliable functioning in the AR15 weapon system. It also offers rapid expansion, high fragmentation and little retained weight. This round is intended primarily for situations where its' limited penetration, extreme fragmentation and reduced ricochet potential are desired. 40 grain anything is a VERY bad idea from 11.5.  It's a bad idea from 20" too, frankly, if you are considering bipedal targets. Evil_Ed: To understand this start with the Ammo-Oracle's note on:  Q. So which ammo is better, M193 or M855?  And what is all this discussion about fragmentation?  Are these dum-dum bullets? Any TAP under 75 grain is an underperformer for self-defense, unfortunately.  Penetration doesn't make the critical 12" requirement. corwin1968:  I would suggest 68 grain OTM, or perhaps 69 grain OTM Sierra Match King.  These are lighter than, say, 75 or 77 grain rounds, and will penetrate through walls and such less as a result.  They will still approach the 12" mark for penetration and tend to fragment down to lower velocities.  I doubt that you are, however, even going to get fragmentation out of them from an 11.5" Depending on the construction of the walls where you are you might want to move up to 75 grain or 77 Grain Nosler (but not SMK).  I would actually suggest the 77 Grain NATO Nosler loading from Black Hills (since the extra velocity is going to be really important from an 11.5"er.

Projecting where I live onto where he is...quite frankly, a foot of penetration into anything would scare me. On the far side of one wall is a family of 3 with a 2 year old, on the far side of the other wall is a 65+ year old who's about to retire. The slightest chance of a bullet going through either wall would be catastrophic. I wouldn't mind it penetrating the floor (the ass who lives below me has supernatural hearing, and bangs on his ceiling every time I turn my headphones up), but I digress.

I'd rather shoot the bad guy 4 or 5 times and not have the rounds penetrate the walls (or if they do and go through, nothing but fragments exit the other side). Around here, walls aren't a foot thick, and any chance of actually having a bullet go all the way through with enough velocity to even harm someone...not good. Getting a scratch while standing 3 feet behind the wall the bad guy happens to be standing on the other side of, is unacceptable as a civilian (if I miss )

Hence my recommendation of 40gr TAP...it won't drop the bad guy in one round (unless you go for a headshot), but it also won't accidentally kill people who aren't the bad guy. In this case, IMO, less is more.

what is your wall,floor , ceiling construction?

"definate"?

It's hard to say what the best Tweaker Killer would be.  Pima county S.O. uses 55gr HPBT's in their M4 Commandos.  That's what I would pick.

I think a suppressed 11.5" AR would be an excellant choice for the short ranges typically encountered in home defense situations provided you usea medium weight hollow point. My choice would be the Winchester 64gr. Power Point Plus.

Quoted: I think a suppressed 11.5" AR would be an excellant choice for the short ranges typically encountered in home defense situations provided you usea medium weight hollow point. My choice would be the Winchester 64gr. Power Point Plus.

I would really recommend against this round.  It will penetrate barriers, like drywall, excessively, particularly as the velocity lowers and there is less "explosive" impact.  I would also recommend against surpressing.  It's going to reduce velocity even more and therefore increase penetration in barriers.  Why exactly do you want that weapon quiet anyhow?

Quoted: "definate"? It's hard to say what the best Tweaker Killer would be.  Pima county S.O. uses 55gr HPBT's in their M4 Commandos.  That's what I would pick.

I'm not sure I could endorse this round either.  55 grain in HP isn't going to give enough penetration in tissue to cause the kind of damage you need to deal reliably with sober bipeds, much less methed-up individuals.

.223 and 5.56 are safer indoors (with respect to overpenetration) than even 9mm JHP rounds.  This is because the velocity is so high and the rounds so light with .223 that nearly explosive fragmentation results after impact with things like drywall.

This Article on .223 for CQB is a good primer on .223 and 5.56 indoors.

In general you want rounds that yaw quickly and are zipping right along.  In a 11.5" weapon the velocity is slowed.  This means you need to make sure they yaw quickly.  That's why I still recommend the 68 and 69 HPBT rounds.  Both will penetrate interior walls less than handgun rounds and that's data that has been generated by the FBI’s Firearms Training Unit.  Both also consistently show 12" of penetration in tissue, a critical performance metric to make sure bad guys (particularly stimulated ones) don't get back up.

I know that it seems that quick and light rounds (55 grains and under with HP or other not FMJ structures) are a good idea here.  They just aren't.   This is because the nature of penetration of rounds through drywall v. through tissue is somewhat counterintuitive.

The FBI has done all the work for you here already.

Hrm...I stand corrected after reading that.

Guess I should stock up on something heavier than the Q3131A I use as my go-to load..

Quoted: Hrm...I stand corrected after reading that. Guess I should stock up on something heavier than the Q3131A I use as my go-to load..

q3131a is a decent defensive load.  M193 rounds (q3131a and XM193 for example) generally hit 12" without a problem inside of 150-200 meters or so.  As a defensive load that you can get a lot of easily and cheaply, it's a fantastic round.  It can be improved on, certainly.

In order of improving terminal performance I recommend:

55 Grain FMJ (M193)
68 Hornady OTM / 69 SMK OTM
75 Hornady OTM
77 SMK OTM
77 Nosler OTM
100 OTM

Personally, I have 5-7 x 20 rounders filled with the NATO loading of the 77 grain Nosler in different spots as my "go to mags."  The rest of my storage or SHTF ammo is M193.  (Either Lake City or Q3131a of recent vintage).

I appreciate all the replies and the linked articles were very interesting!  

I'm not clear on some of the terminology.

68 or 69 HPBT = hollow point boat tailed?

I have no idea what OTM stands for.

Sierra King was mentioned but what are some brands I should look for in the 68 or 69 HPBT?  Should I go with 1/7" or is 1/9" adequate for my needs?

Again, thanks for the great info!!!

OTM = Open Tip Match

You're correct on the HPBT.

The 68gr is made by Hornady and the 69gr is a Sierra.  Both will be fine with a 1/9 twist barrel.  If you already have a 1/7, then I'd move on up to the 75/77gr loads.

move.

build your commando somewhere you won't have to use it.

Quoted: move. build your commando somewhere you won't have to use it.

Hush!

We're not discussing common sense here!

corwin1968,

You ain't a shitten about the meth capital of the world!

Go with the TAP 40gr, you don't want too much penetration in a apartment complex, GOD forbid, what if you miss! This is exactly why some police & entry teams use the stuff! No, it's not the best performing round, but it may be in your situation. Federal & Cor-Bon, both have some 40gr ammo.

Just my 2 cents, nothing more!

Go Sooners!
teamroper2004

But he is in an apartment.

So he would be at closer ranges.

Would that make a difference?

CRC

Have you given any thought to a shotgun.  I understand the penetration issues with #00 buck, but at the ranges we are discussing, I think an 18" barrel with #4 buskshot would be about ideal.
Additionally, it is more "politically freindly" too.

40gr TAP from an 11.5" barrel:

(From Hornady's testing)
Total Penetration: 5"
Entry: 0.5" (length of the 'neck')
Depth to Max Cavity: 4.5"
Percent Fragmentation: 100%

The deepest penetration was with a 20" 1:7 twist Colt at 6"  the 20" 1:12 twist Colt had the 2nd deepest at 5.75" - the rest of the barrel lengths (from 8.38" to 24") with in the low 5" range.

Thanks.

CRC

DISCLAIMERThis carries little/no scientific weight but is an interesting experiment/observation for entertainment purposes only.DISCLAIMER

Shooting into water-filled milk jugs at 50 ydswith 68gr Hornady BTHP (handloads, manual says 3000 fps muzzle velocity, I assume 24 inch barrel) using AR-15 with 11.5 inch barrel.

Bullet penetrated 3 jugs lined up and fragmented 43% , the bullet and jacket had seperated and what was left was in the third jug.

Also shot  jugs with Sierra 52gr OTM (handloads at published vel of about 3300 fps).

Bullet fragments penetrated into the 3rd jug, but most of the bullet frags where in the second jug. Bullet fragmented 100%

Also shot with 55gr FMJ winchester USA commercial .223 (neg control).

Bullet penetrated 2 jugs and veered off  missing the last  jug, found it on the ground. I was flattened and the tip was bent but the bullet did not fragment.

If considered in relative terms these result are similar to actual ballistic testing.  68gr penetrates the farthest but still fragments pretty well. 52 gr doesn't penetrate as far  (or at least in mass) and violently explodes. 55gr FMJ does not have enough velocity to fragment and doesn't.  

Another interesting addition would be M193 spec ammo to see how fragmentation and penetration compares relatively to the other rounds.

It MIGHT be safe to say (because some high profile people have stated that water will determine fragmentation but NOT penetration) that 68 gr Hornady BTHP will fragment fairly well at 50yds out of an 11.5 inch barrel, and fragmentation will be even better at closer range/higher velocity. A variable that might put some doubt into my test is that the plastic of the jugs might accelarate fragmentation giving a false positive result.


FWIW

Cool experiment!!  

Was there any space between the jugs?

I've been thinking of doing something sort-of like that but I was considering building several 1'x1' "walls" out of 2x4's, sheet rock, and insulation.  I'd like to set up 1 foot square panels that represent a typical sheetrock wall and put something behind them to simulate "things" in the next room/apartment.  I would like to actually see the penetration effects of my AR versus my 9mm with different ammo in each.  I know the FBI has done this but it would still make a fun weekend project anyway!

Quoted: To get somewhat correct results, you should be using milk CARTONS (i.e., paper) and not jugs (plastic).  The plastic of the jug is a very hard surface for the bullet travelling at over Mach 2, and changes the outcome of the testing far too much.  Milk cartons give roughly similar fragmentation results as gelatin, though of course you can't observe the pattern. -Troy

Great point Troy. Cartons would also line up better.

It's easier for me to collect the plastic ones cuz we don't buy milk in cartons  Looks like I'll be doing some dumpster diving for milk cartons .  Might as well take a  "work for food" sign along too, might get some ammo fundage.





corwin-no space between jugs, they were back to back. Yours would be a fun project too especially if you had access to scrap building materials at job sites. You could experiement with all sorts of combinations.  Beats shooting paper all the time at the range (as long as we clean up our mess).

I understand tatjana, but due to the relatively light mass of the #4 shot, i dont think penatration would be a problem with apartment walls.  Remember mass times velocity equals momentum; therfore, it is this lack of momentum coupled with the inherent lack of sectional density of this specific shot size, that would mitigate unacceptable penetration.  

Or not, whatever...

Damn i cant spell after thirteen beers!!  

I disagree with the assertion that 12 gauge #4 buck and smaller shot would not be adequate for self defense.  At close range, a load of shot is going to act like one mass, but penetration is reduced.  Just test on some dry wall and see what penetrates and what doesn't.  

What about exotic frangible bullets in any caliber?  I know they aren't ideal, but I would bet a 15 or 30 round mag filled with them would get the job done.

Also I think you will get much less permanent hearing loss from a 18"-20" 12 gauge, than from a 12" commando ar-15, from shooting indoors.    

Roger That Mark 13.