Tag Archives: Ammunition

Home Defense Ammo: Overpenetration

A recent exchange with fellow blogger MysticalRaven on wall penetration risks- more specifically Overpenetration– led me to research the topic a bit. Safety is very important to me and I want to be certain that I have ammo that is safe to use if a home defense situation occurs. The term ‘safe’ implies not only safety of my loved ones but also the safety of people in the homes near me and even people walking or driving by. 

It turns out that, contrary to what retailers in my area say, Frangible Ammo has a bad track record for overpenetration- especially when encountering surfaces like drywall. And then there was a new product announcement….CorBon recently released a new .223 ammo (which also works in 5.56 rifles dude) called Urban Response. They claim that it is the ideal rifle self-defense load for close quarter urban environments such as subdivisions, apartment complexes, and mobile home parks. One would think there is a reasonable market niche for such a product since Armalite-15 style rifles have been flying off the shelves at record rates. Not only that but many people like modern sporting rifles for their utility- including using them for self-defense. Even kids have successfully defended their families using modern sporting rifles. It’s not that uncommon for law-abiding citizens to defend themselves with this sort of rifle btw- no matter what the mainstream media fails to report in the “news”.

Back to the point- how could this CorBon ammo work? I mentioned the bad track record of frangible ammo (frangies) in the event a target is missed and it’s tendency to pass through walls. I’m a little skeptical about the safety of this sort of product- look at the results of the Mesa, AZ PD tests. There is also lots of useful pistol and ammo performance results here . 

CorBon Gel block testing shows 10″ penetration- take another look at the photo at the top of this post. Newer exterior mobile home walls are about 4-6″ thick. Typical interior walls separating apartment units could be up to 8″ thick, but interior walls of an average home are about 6″ thick and exterior walls of the average home run about 8″. Does 10″ penetration make anyone else nervous looking at these figures? The main wound channel stops at about 8″ but not entirely. Even so, 8″ penetration grouch a 6″ wall doesn’t sound safe to me.

A quick call to Cor-Bon revealed some answers- according to technicians at CorBon:

This ammo features a very thin jacket, pre-serrated, internally scored internal projectile. It’s designed to reliably fragment upon impact. As the bullet penetrates barriers it fragments – to a degree that while a fragment will likely pass through a wall, it is unlikely to have the mass or velocity to injure someone.

The 10″ penetration test results also demonstrate that the ammo is designed to not exit a human body with enough velocity and mass to cause serious injury. 

Keep an eye out for press coverage on CorBon Urban Response- they said that detailed performance and test results are committed to a few articles we should see in the next month or so. If this ammo looks like something you want I humbly suggest that you buy it soon before the word gets out.

Safety Considerations for Home Defense

Choosing a home defense firearm is important. What about defensive ammo? Look at what Rich Graham shows us regarding residential wall penetration from a standard modern day musket:

If you plan to use a rifle for home defense purposes it's very important that you spend the time and money to acquire frangible ammo. If you plan to use a handgun be certain you have proper defensive ammo for home carry.

Remember: once you press the bang switch you own that projectile until it stops moving.

Ammo Shortage Update


Interesting news yesterday – a colleague stopped by my desk at the cubicle farm to share a hot tip: our local Wal-Marts in about a 50 mile radius are getting ammunition shipments daily- even the elusive .22 LR bulk packs. Prices are also at familiar, pre-panic retail prices.

The downside: 3 box per person limit- but that's what we can expect to endure until a surplus returns to the land of brick and mortars- and the limit is the reason the shelves aren't picked clean by the first panic buyer who sees them.

After sharing this info with familiar faces at my LGS (local gun store) I heard some rumors on how this happened:

  • Both Wal-Mart and Gander Mountain are rumored to have funded additional factory buildings for large manufacturers like Winchester and ATK – in exchange for exclusive rights to the rounds produced by those facilities.

It's a good story- however I'm reluctant to believe it. The primary reason for my doubt is that a move like this should be big news. I can't find a mention of this online or on either company's corporate site. No corroboration= not true over here. If you have sources to confirm these rumors please post links in the comments section.

Also do your best to refrain from paying inflated ammo prices– it will help drive liquidation of the hoarder stashes that are paying high prices. There is no reason to pay $6 for a box of 50 .22 rounds.


Initial Impressions of my Chrony F1

Recently I decided to quit borrowing other people's chronographs and instead purchase my own.

A basic Chrony model F1 with a tripod costs about $100 from Amazon. With the optional pushbutton remote the F1 is capable of displaying the stats for several strings of 10 shots (either 6 or 10 if I recall correctly). You can either buy the remote from a retailer for $20 or make a simple remote with <$10 of supplies from radio shack.

I found that it was easy to use, worked great with my homemade remote and helped me capture solid data on my LilGun recipe for 220gr 300 BLK Subsonic handloads.

One note to other buyers: although the directions claim you don't need the sunshades over the top of the cameras on a cloudy day it's worth leaving them on all the time- on this particular cloudy day I had to aim really low to get readings from the 9″ barrel and ended up aiming more closely than intended…


300 AAC Blackout Load Recipe: 220gr SMK using LilGun

When I started researching recipes for 300 BLK subsonic loads the recommended powder was Accurate 1680. The Interweb phenomenon took hold and now there is a false impression that 1680 is the only powder that works for subsonic AAC Blackout loads.

Slowly the truth is getting out there- and I can now personally confirm success with LilGun as an alternative to 1680 for subsonic BLK loading. Also LilGun requires less charge per round than 1680– so it’s even more efficient– it’s my new preferred powder. More alternatives here– I plan to work on IMR options next.

Recipe created and tuned using a Lee Precision 4-hole Turret Press with double-disc powder throw and load both factory BLK brass and 5.56 brass trimmed to 300BLK specs. I recommend using LC brass when possible as I find its the most consistent. I still use CCI #400 primers, although you should note that these primers are a little soft so CCI #41 primers are best.

Performance:This recipe successfully cycles both a carbine length upper (and gas system) with a 16″ barrel and also a 9″ pistol length upper, no suppressor. No bolt hold-open on either upper, but that could be the PMAGs I used. No signs of overpressure or instability. Chrony readings coming soon are here and I had no problems dinging a 100yd target with these without hold-over.

NOTE: Users assume all risk, responsibility and liability whatsoever for any and all injuries (including death), losses or damages to persons or property (including consequential damages), arising from the use of any data, whether or not occasioned by publisher’s negligence or based on strict liability or principles of indemnity or contribution. kR-15.Com neither assumes nor authorizes any person to assume for it any liability in connection with the use of any data.

Caliber: 300 AAC Blackout (300 BLK)

Projectile: 220gr Sierra Match HPBT

Primer: CCI Small Rifle Primers (no. 400)

Powder: Hodgdon LilGun

Measure: 8.8gr

Lee Auto-Disc setting(double disc): Top Disc 0.30 | Bottom Disc 0.30

Min OAL: 2.140

Max OAL: see discussion below


Regarding OAL I had to experiment to find a length that fed well. Here is my thought process to arrive at the OAL I set my dies to:

This seems like a pretty big tolerance. I set my seating die to give me the longest possible cartridge-about 2.220 and ranging up to 2.240. Some factory ammo I purchased didn’t feed well due to FTC (Failure to Chamber). It turned out that they were the short end of the SAAMI OAL specs. Some scouring on forums and experimentation proved that longer OAL fed better : no FTCs on any of my BLK cartridges since this change.


The beauty of using these high mass projectiles in a modern sporting cartridge is that they pack a serious punch and don’t use much powder– a nice bonus when supplies are scarce or you’re on a budget.


Coopers 4th Law: especially important with subsonic ammo

Not too long ago I had a very eye-opening experience during an afternoon plinking outing. We were shooting short range at a woodpile at the bottom of a substantial hill. I was firing different rounds (mostly subsonic) through a chronometer – slow pace, very controlled fire, and could account for every hit.

Afterward I checked in with my friend, who generously allowed us to shoot up his woodpile, and he told me he could hear ricochets flying over while working in an outbuilding on top of the hill (not at the edge of the hill but more like 30 feet in from the edge).

Woah. That may come as a surprise to you- it sure caught me off guard.

The problem is velocity– subsonic ammo isn't moving fast enough to split or flatten projectiles. This leads to slight deformation of the projectile and subsequent tumbling. They end up bouncing around like “rubber balls” according to some associates interviewed in my research.

This is not completely intuitive because the sound of the shot going off masks the sound of the ricochet. Supersonics are probably doing it too sometimes but the SMKs are really prone to ricochet.

The fact that a woodpile isn't a sufficient backstop was another surprise–my research into this topic has shown that railroad ties and in some cases dirt birms aren't always enough either.

Bottom Line: be sure to know and follow Cooper's 4th Law: know your target and what lies beyond it. Please be safe out there.

Where I get my BLK Brass

While you can make your own BLK brass I don't have a bunch of .223 or 5.56 brass just laying around. It's not difficult to make your brass but right now I'd rather focus on other things. The problem with ordering brass online is that you don't always know what the quality will be like (for example all my FTCs from blackoutbrass.com) and prices vary widely.

Recently I found a place that delivers the best brass I have seen to date at a fair price: 300aacbrass.com . I bought a sample 100 pieces of LC brass and am very impressed. Outstanding responsiveness too- never waited more than 24 hrs to hear back from them.

  • Mirror shine on the cases- you can see into them while loading
  • Every piece ran through my Lee dies like butter
  • Test firing went as expected- no problems feeding, chambering, ejecting. Fired cases look good.


How often do you test your Carry Pistol?

Most police departments fire their duty ammo every year and replace it with factory new ammo. It's a good idea to do this for your concealed carry weapon too- you don't want to press the trigger and hear *CLICK* at a critical moment, do you?

It is important to have two types of mags and ammo- one designated training set and one designated carry set. Training mags get tossed around at the range, run lots of cheap, dirty training ammo and it's OK if they get beaten up. They should be marked or painted to make it impossible to confuse them with carry mags.

The logic behind this is that you keep the gear you depend on to defend yourself pristine. Feed lips on mags can get bent when mags hit any hard surface just so- including the ground. If this or other damage happens the mag may be good for training but will be more prone to an occasional malfunction than one that has never been dropped. Why take an unnecessary risk by using equipment that is more likely to fail?

If you clean your gun after some range time and load it back up with carry ammo afterward (such as Hornaday Critical Duty ammo, projectile pictured above) many would suggest firing your carry ammo once every 12 months. This stems from concern that solvents will penetrate the primer pocket and render the primer itself inert. That has the potential to be an urban legend though- instead think of it as practice. You may run across problems right under your nose by practicing with your carry rig. Tomorrow I will give the lowdown on my own scary equipment failure, analysis and response.


Subsonic 220 SMKs Obliterate a Concrete Block

While many (including myself) are disappointed with the expansion of the 220gr BTHP (aka Sierra MatchKing aka SMK) at subsonic velocities this video is hard to dispute – the cinder block doesn't hold up too well to a few rounds. I won't hold it against anyone who skips the first half of the video…crossbows just aren't that interesting to me…


Chronograph results- at long last

I finally got to borrow a chrony and made the most of it- here are the results of testing the recipes listed here on an 85 degree summer day. Test results are the average of 3 shots and were fired out of a 16″ barrel- so velocities are higher than what you could expect from a shorter barrel.

I also noticed something interesting while testing: the PMAG30 doesn't hold open when empty but the USGI and Promag mags do- even with subsonic loads.