Cor-Bon DPX disappointment

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DoubleTapDrew

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My Dad and I did some shooting today to try out some 380 loads for the pocket pistols (Kel-Tec P3AT and Ruger LCP).
We did the wet phone book method at about 10ft with 3 different 380 loads, 3 9mm loads, and a single .45acp (didn't bring any other .45 ammo) for kicks.

The 380 loads were: Cor-Bon DPX 80gr, Speer Gold Dot 90gr, and Federal Hydra-Shok 90gr. All were shot through a Kel-Tec P3AT.
All of the 380 rounds penetrated fine but the DPX didn't expand and the hollow point was filled with phone book. Hmm. I thought maybe it was a fluke and shot 2 more rounds with the same results! We thought maybe it needs a more fluid medium to expand so put a 1 gallon milk jug filled with water in front of the phone books. Same thing (only this time the HP wasn't filled with paper).
What the heck is going on? This is supposed to be the end-all-be-all 380 ammo and it didn't even expand! Pics of the bullets are below, the far right DPX round was the shot through water then phone book.

For the other 380 ammo the speer gold-dot didn't expand much at all (half the pedals bent over, the rest are intact) and the hydra shock expanded nicely. The center "post' on the hydra shok was deformed but it didn't clog with paper.

For the 9mm ammo I was using 124gr +P Remington Golden Saber, Speer Gold Dot 124gr +P (actually Georgia Arms loaded ammo with those bullets rated at 1200fps on the package), and our practice ammo: 115gr hollow point handloads (I think they are remington or federal bullets). These were shot through a Glock 26 (3.5" barrel). The Golden Saber separated and left the jacket behind, the core spread a little but wasn't much more than a wadcutter. The gold dots from georgia arms did very well and look like most of the pics I've seen of expanded gold dots. The handload did way better than expected, stayed together and mushroomed nicely.

The 45 round was a 230gr Federal Hydra-Shock and did what it's supposed to, bust through and open up. The jacket peeled a little unevenly (check out the side-view pic) but it looks like it'll do the job.

My question is what's the deal with the DPX 380 ammo? I was under the impression this was the ultimate 380 ammo (and it should be for $1.50 a round) but it didn't even open up!
 

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typically either gold dots, and federal hst are king of hollow points in most tests. the hst seems to consistently expand the largest, but can suffer from jacket separation. gold dots are typically consistent performers on expanding though the expanded diameter is less than the hst, but doesn't have jacket separations.

something to consider though, velocity is a big factor in expansion, and these tiny guns have short barrels. the short barrel versions of hollow points tend to expand much better coming out of short barrels. the short barrel hollow points have a larger cavity, and some guns may not like to feed them.

another factor is a lighter round loses more velocity out of the short barrels... here is a little bit of a read on that...
http://www.m4carbine.net/showthread.php?t=23210
 
DoubleTapDrew said:
I do have HST for 9mm and .45 and will try those in the future (and pick up some in 380). Just curious about why the DPX in .380 was so poor.
it may have to do with the dpx rounds being 80 grain as opposed to the 90 grains in the others... the link i posted talks about the differences in bullet weights for short barrels and expansion as opposed to how they act in full size barrels.
 
1,000 fps is usually the minimum velocity to begin to get reliable expansion. The 380 barely achives this at the muzzle. What you experienced is rather typical of the 380. Since some bullets for the 380 are also loaded in 9mm, the hardness is rated for expansion in the 9mm and it's higher velocity. Another problem as well with making a bullet soft enough to expand well with the 380 is that due to the minimal weight and velocity a 380 round that expands well, may lack enough power to penetrate to vital organs. I have found that a 85-90 swc style bullet gives good penetration, while cutting a nasty wound channel. The problem with those is they don't feed well in all autos due to their short nose. The 380 is right at the threshold of power, with this round penetration to vitals should be the first goal, with expansion if and when you get some. In reality, the ball round is a fair consideration offering both deep penetration, and reliable feeding.
 
This is going to sound really weird, but those don't look like cor-bon dpx projectiles to me. The cavity looks too small, the relief cuts penetrate to the exterior ogive of the bullet, and the top looks "petaled" like a Winchester pdx.

Check this out: http://www.dakotaammo.net/Self-Defense-DPXreg/380-Auto-80gr-Self-Defense-DPX/DPX38080-20/200/Product

Compare the image to the projectiles in the op's image looking at the three things I mentioned.

I noticed because cor-bon have the widest hollow point cavity I have ever seen.
 
Thanks for posting. Interesting photo's.

Right now, 9mm is as low as I go for carrying. When 380 ammo supply dried up around here I parked or sold my 380's as I was able to get my hands on enough 9mm to keep me content. I think I may try the 9mm Georgia Arms ammo though, it looks interesting in your tests. I use the Remington Golden Sabre for carry in my P-11 now but haven't tried any tests of it like you have.

For carry in my 45's I use Winchester 230 gr hp (not +P), need to try a short test to see how they compare to your results.
 
The DPX's don't look right because they may have caved in after hitting the media, in this case the phone book. These look to be a velocity issue because when I tested the DPX's I carry in my 9mm and .45 every round expanded out of the 10 of each caliber I shot. I don't own a .380 and have never tested ammo for it either so I cannot weigh in more than just a 'guess' as to why it didn't expand.

Damian
 
I have had similar results with the gold dot, never tried the cor-bon. I have tried the buffalo bore +p .380 HP, ans still no reliable expansion from my LCP. The only round I have tried that was acceptably reliable in the expansion dept. from a short barrel was the win. silvertips. When I tried the same tests in my wifes PK380 (3.6 in barrel) the gold dots did expand on occasion, as did the buffalo bore. Considering the minimal penatration in this caliber though, text-book expansion may not be the most desireable quality, as in my opinion, it would limit penetration in worst-case scenarios.
 
When you are talking a lightweight, slow bullet from a short barrel, I am more concerned with adequate penetration than I am with expansion.

Some .380 bullets after expansion won't penetrate sufficiently through heavy clothing to penetrate vital areas. I know a number of people who choose hardball for that reason.

Me? I am sticking to .45 ACP, with an occasional day carrying .40 S&W.
 
These look to be a velocity issue because when I tested the DPX's I carry in my 9mm and .45 every round expanded out of the 10 of each caliber I shot.

All of the 380 rounds penetrated fine but the DPX didn't expand and the hollow point was filled with phone book.

Could it be a bad lot issue?
 
From the website posted for the .380 corbon round: http://www.dakotaammo.net/Self-Defen...20/200/Product

"The all-copper bullet construction conquers hard barriers like auto glass and steel while still maintaining its integrity. This is an optimum load for Law Enforcement.

- Deep penetration on soft tissue 12-17 inches.
- Easily conquers hard barriers like auto glass and steel.
- Reduced recoil due to lighter-weight projectile.
- Lead-free projectile.
- Environmentally friendly!
*CERTIFIED: CALIFORNIA LEAD FREE*

Caliber: 380 Auto
Bullet Wt.: 80gr Self-Defense DPX
Velocity: 1050fps
Energy: 196ftlbs
Test Barrel Length: 2.5 Inches
20 rounds per box."

What struck me first was the "all copper construction" - copper is not as soft as lead and given the velocity reported, "1050 fps" - I would think that expansion would be problematic - even given the hollow point construction. The quote that "...bullet construction conquers hard barriers like auto glass and steel while still maintaining its integrity." Leads me to think that penetration is what they are selling more than expansion.
 
This is going to sound really weird, but those don't look like cor-bon dpx projectiles to me. The cavity looks too small, the relief cuts penetrate to the exterior ogive of the bullet, and the top looks "petaled" like a Winchester pdx.
Could it be a bad lot issue?

Good points, I'll have to look into this further. We bought 3 boxes of it from midway and they came in the typical DPX boxes. Hmm. I'll have to get out the chronograph and dump out the other rounds to see what the cavity dimensions are, they did look a bit small compared to what I've seen for DPX.
 
Well, with a .380, I'd be more concerned with penetration, and the DPX is likely going to do just that.
 
Mack Barnes X bullets are a first class hunting bullet and have been for many years. They are copper but are treated so they do expand well in live tissue. They did have some trouble not with expansion 20 years ago with pedals comeing off but fixed that quickly. I don't put much faith in all the different types testing mediums being compatible with live tissue. Even the standard gelliton is only a percentage comperison. I have seen different Barnes X bullets used to hunt deer ,by me, and i can say that in a 357 and my 7mm rem mag are deviastating on deer. Barnes is known to do there home work on the many different types of bullets they make so maybe wet paper ain't a real enoungh medium to beleive in. Now saying all that I only use them as a hunting load. All the regular hp rounds have had some trouble ether feeding or expanding in heavy clothing and we all know this. So my carry ammo is Hornady's CD ammo in my 9mm and 38sp. They were designed to work at slower velocity are are all made in house. May not be the fastest are best under perfect conditions , till something better comes along.
 
I fired some of the Cor Bon DPX .357 loads from a 3.1" barrel into milk jugs packed with wet newspaper, and experienced very inconsistent and dissappointing results. While most rounds expanded to some degree, they were not reliable.

All Speer Gold Dots I fired in the same media, regardless of caliber, produced picture-perfect expansion. They are the only expanding bullet I carry for defensive purposes.

I think the DPX bullet as WAY overrated. (and overpriced, too)
 
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