I have a few questions regarding the terminology in the article Best Choices for Self Defense Ammo http://www.ar15.com/ammo/project/Self_Defense_Ammo_FAQ/index.htm#BARRIER_BLIND_LOADS. I am bit new to learning the ammo types and terms, so bare with me please.

Here are the questions I have about content in the article as I read:

1.“If barrier penetration is NOT an important factor AND your rifle can stabilize them (minimum 1:9 twist rate):”

What does this statement mean? What means barrier penetration is NOT important? Please give an example. Does this mean, I do NOT need the bullet to travel through any barrier before hitting the target? Meaning that when I shoot my intruder nothing (barrier) will be in the way of muzzle and intruder body but air and the intruder clothes?

2. “If barrier penetration IS an important factor:”
What does this statement mean? What means barrier penetration is important? Please give an example. Does this mean when I shoot at something (intruder only), I need the bullet to travel through the wall, glass, or even wood door to hit the target? Meaning that the bullet can go through a wall and still be lethal?

3. So barrier blind (or bonded ammo) ammo means, the bullet can pass through a barrier (wall, glass, wood, etc) and NOT expand or fragment and hold bullet weight and velocity and STILL be lethal on the tissue, correct?  If yes, then if a homeowner wanted a bullet that will START to expand, lose velocity, weight and fragment to pieces after the bullet hits any barrier (or tissue), the homeowner will NOT choose barrier blind (or bonded ammo) ammo , correct?

Thanks for the help

Sounds like you got it.

"If barrier penetration is NOT an important factor AND your rifle can't stabilize the heavy 70+ grain bullets:"

What does stabilize mean and how do I know if my 1:9 twist rifle (Smith & Wesson M&P Sport II) can stabilize 70+ grain bullets?

1/7 are recommended for stabilizing 70 plus grain

shoot some.  It wont hurt your rifle.

Buy a box of 75 or 77 grain ammo and shoot it. If your groups are good and you have no key holing, you're good to go. I would shoot paper targets at several distances to see if you get key holing. 25, 50, 100 and 200 yards should be sufficient for SD distances.

Some 1:9 barrels do better than others. As said in the above post, 1:9 is not recommended for bullets over 68 grains. Some will stabilize the longer bullets. It is about the length of the bullet.

What does key holing mean?

Bullet impacts target sideways, reminscent of the shape of an old fashoined key lock doorknob's keyhole.

Hello,

What does SMK, OTM, JSP, TRU mean?

Thank you Lightstriker,

So if I buy 77gr and shoot it and it start key holding like your example , does that mean my rifle can not stabilize 77gr, and I need to reduce to lower size like 62gr?

Pretty much.

Also,

SMK = Sierra Match King
OTM = Open Tip Match
JSP = Jacketed Soft Point
TRU = Tactical Rifle Urban

Thank you so much.

"Barrier" in this context means car body and auto glass and solid wood or steel doors. It is not referring to mere clothing, plastic and foam doors, or even drywall.

Thank you very much StevenH

Hello,

Still reading.

Sierra 69gr SMK loads

What the "loads" part of this mean? I can't buy Sierra 69gr SMK loads ammunition ?

Thank you so much Tigwelder1971,

The distances I will be shooting in home defense is not longer then 15 yards (not longer then 20 ft).

My twist is 1:9 and barrel length is 16".

I will just have to try the heavy gr at short distances

What does loading mean? Does this mean people make their own bullets? Why not just buy from the manufacture?

Me too. I have a shotgun as well. The AR will be reserved depending on how many intruders come in the house. I do not have any property to protect. My concern is intruders into the house, then I take action. I can not shoot someone outside of my home, unless they are standing outside shooting at my house.

These tasks i am doing is only if I check my security cameras and i see alot intruders entering my house. Plus the AR is better accurate for me.

Under no conditions should you reserve a weapon. Always come out with the most effective weapon you have. You do not know how many attackers there are, so use the very best you have. You don't know if they'll stand and fight, take cover, use teamwork, etc, so use your most effective weapon from the start. Your most effective weapon is your AR.

As to the ammo.

You're really overthinking this.

If you have a 1/9 just get something in the 55gr to 69gr bonded or lead /spire point type.   Any of them will work well. Just don't use varmint loads.

As far as your question about the meaning of loading. In this case, it means that that particular offering / product, and has nothing to do with hand loads.

The reason for hand loads, since you asked, is you can load better, more reliable, more consistent, and more accurate ammo, designed for your rifle, cheaper than you can buy factory, and the better the ammo, the bigger the cost difference.

Seriously though, just get a couple of types that the members are recommending in the weight range that the 1/9 works best at, and shoot them at a decent distance, furthest you can, and see which ones are most accurate and reliable in your rifle. When you get that done, then buy a case of them.

I really don't fuss too much over it myself. I have mags loaded with M193 55gr, IWI 77gr Razor Core, and M855 62gr green tip. Those are factory loads. I also have mags loaded with Hornady 55gr FMJ that works like the M193, but is more accurate, also Hornady 55gr Spire point ( lead tip ). I normally like the Hornady 55gr Spire point for my SD loads, though I will use the IWI 77gr Razor Core as well. I don't feel under gunned with any of them, and at home defense distances, I'm not.

I even have a mag loaded half 55gr FMJ Hornady, and Half Hornady 55r Spire point. I was loading the FMJs in the mag, and since the spire points were right beside them in a loading tray, I started accidentally loading them. I was watching tv, and when I realized it, I figure, well, whatever, I'll finish it this way, because it really doesn't matter.

At HD distances, picking one of them over the other is pretty much asking you if you'd rather be run over by a Ford, or a Chevy, or a Dodge pickup, at 150mph. They are all going to kill you and you wouldn't know what hit you unless you asked Saint Peter what the hell happened when you got to the pearly gates.

BTW, I sold my ARs a couple of years ago due to bills, not for a dislike of the platform, had a 6.8 ARP and a .223 Wylde ARP, and when I got the money back, I bought a Tavor due to wanting something different. It has a 1/7 twist.

Thanks pavlovwolf,

What do you mean by more reliable?

When I buy these different ammo, how will I know if they are reliable?

More reliable in that when you hand load, you have control over the quality of the final product. Every ammo company produces, from time to time, ammo that won't fire when the primer is struck for various reasons, or, a round with no powder or low powder and only a primer. In my decades of loading, I've never done that, ever round has gone bang, correctly, and that's with around 90K pistol rounds, and 20K + rifle rounds. I am monitoring every step closely.

Factories do a great job, but they have an automated process , and while there are electronics checks to catch any issues, those checks do fail.

I've had failures with just about every brand, and most quality brands and types. There's no way to know if there's nothing visually wrong. Stay away from Remington and remanufactured and your chances of failure will be reduced dramatically. I've had Rem ammo in .223 where primers were seated backward, cases were twisted, bullets seated sort of sideways, and in the same case as those, no neck tension, where the bullets had fallen into the case, and wild variations in powder charges. Only about half that case was right, but this was during the panic and there wasn't anything else on the shelves anywhere.

I fixed all the problems except the ones with case damage by pulling the bullets resizing the cases, a reloading them. Some I was able to just use a
Lee crimp die to get the tension correct so the bullet stayed put in the case.

Hello,

Should 223 Remington 55 gr (or 73gr)  FTX® Critical Defense be in the article?

Or should a gel test be done first before considering this ammo?

Not too confuse things, but fragmentation is a large part of what made / makes 5.56 ammo work.

The original M193 ammo was a 55 grain FMJ bullet.  Due to its speed, the bullet exhibited great terminal effectiveness because it would penetrate 5-6" in, the begin to turn sideways (keyhole), the rotational forces on the bullet would then often cause the bullet to fragment (rupturing the jacket and spewing fragments) with very devastating wounds.'

Most 5.56 ammo still exhibits this behavior to a greater or lesser degree.

The illustration below shows the effects of some "Standard" defense Cartridges

While the chart above is useful, it does not include the contemporary barrier blind certified defensive rounds such as bonded soft points such as Federal's load with TrophyBonded Bear Claw bullets, or Speer Gold Dot, Federal Fusion, or my favorites the various Barnes monolithic copper bullets like the 62 and 70 grain TSX.

Where barrier blind performance is needed (virtually always) to ensure at least 12 inches of body penetration and to be able to purposefully hit an intruder trying to use a wall for cover, these newer bullets have much to offer.  I like the Speer Gold Dot for factory ammo, and load my own 62 and 70 grain Barnes TSX.

And, there is a post above suggesting that 1:7 is needed to shoot the heavier bullets.  That is incorrect.  A 1:8 twist, becoming increasingly popular, will well-stabilize ANY bullet (other than tracers) that can cycle through an AR15 magazine.  You don't need 1:7, although it gets the job done, too.

FWIW, the long for weight monolithic bullets are a class unto themselves when it comes to twist, because a 70 grain lead core bullet will stabilize just fine in 1:9, but the very long Barnes 70 TSX is as long as a 77 grain Speer Match King (SMK) and positively will keyhole badly from my 16" 1:9 carbine.

OP would be well-served with Speer Gold Dot 62/64 (probably the same) bonded soft point, the same weight Federal Fusion (also probably the same bullet), the newer Federal Trophy Bpnded Bear Claw (TBBC) 62 or the Barnes TSX 62.   All would be excellent.