Gelatin test: .40 S&W 180 gr Gold Dot fired from pistol and carbine

40 S&W 180 gr Speer Gold Dot loaded over 9.2 gr of AA#7 fired from a Kel-Tec Sub 2000 carbine and Glock model 22 pistol through four layers of denim into calibrated gelatin.

BB: 593.6 fps, 3.4"

Pistol data:

Impact velocity: 1,081 fps
Penetration: 14.5"
Retained weight: 179.7 gr
Max expansion: 0.741"
Min expansion: 0.492"

Carbine data:

Impact velocity: 1,320 fps (approx.)
Penetration: 16.6"
Retained weight: 178.9 gr
Max expansion: 0.781"
Min expansion: 0.538"


A few notes: The chronograph did not catch the impact velocity from the carbine shot so I took a four shot average. Velocities were:

1,312 fps
1,317 fps
1,327 fps
1,324 fps

I was surprised at how much velocity the bullet gained from the longer barrel and I was surprised to note that the faster bullet actually went deeper. I had to double check. The only explanation I can come up with is that the extra velocity pushed the petals back against the shank earlier.

Speer lists the factory velocity as 1,025 from a pistol so I believe that I got fairly close to what they put out but I do not know what powder they use so the burn rate could be substantially different. I did not have any extra factory ammo available for testing.

Cee Zee, I tested 10mm 175 gr Critical Duty (video below) It is certainly a good projectile but I don't believe it to be superior to Gold Dot or HST by any signi9ficant margin. Also, Gold Dot does have very good barrier performance if that's something that ranks high on your list of priorities. Almost any pistol bullet will penetrate sheet metal or windshield glass. It's not about getting through it. It's about how well the projectile performs after penetrating. Some bullets fail to expand after passing through hard objects. Gold Dot and HST usually do very well with barriers. The reason Critical Duty made a larger hole in the wood is that the rubber plug was still able to cause a little expansion in the projectile whereas a traditional hollow point like Gold Dot doesn't experience any hydraulic pressure in wood so it does not expand.


Skribs, I like your explanation. I believe you are correct. Thank you for posting.

Are there any 135 gr .40/10mm that will meet the minimum penetration standard?

Why? All else being equal penetration is proportional to sectional density times bullet velocity.

Click to expand...

For solids, the relationship is close to linear. As velocity increases, penetration increases. As you note, JHPs don't expand the same at different velocities. I don't know the exact mechanisms and Doc Roberts assured me that the expansion RATE is the same, regardless of velocity. I find that difficult to believe but he's got a lot more experience and book learnin' than I do. The SIZE of the expansion can definitely be effected by velocity.

Take a look at the difference in penetration between these two:




And again with these two:






You can see a similar, but less pronounced effect with the smaller variations in velocity between standard pressure and +P loads of the same type and weight on ATK's website, particularly in the tests fired through heavy clothing or IWBA heavy clothing, like my own tests.

http://le.atk.com/wound_ballistics/

Cee Zee, you're missing the point. Performance against auto glass is one important factor but there are several other factors that are also important. The performance over a range of metrics is the reason that HST and Gold Dot are the preferred choices for defense.

Don't get me wrong, Hornady's Critical Duty is a great bullet and a substantial improvement over their XTP line (for defense, that is) but HST and Gold Dot have a longer track record and are well proven designs.

CD hasn't been around as long so it's not fair to compare the number of agencies that choose it, but do you know if any PDs have adopted it?

ATLDave, these results were consistent with tnoutdoors9's test of Underwood 10mm 180 gr GDHP but my own test of a 10mm 180 gr GDHP at the same velocity showed dramatically less penetration. That indicates to me that performance may be somewhat erratic at this velocity.