Yes, the 9mm Ammo Quest continues. I may occasionally get distracted with shotgun slugs or AR15 tests or the new exotic .380 ammo or whatever, but the main grind is to get through these 9mm tests and find what works best and what won’t perform in a 3″-barrel pistol. I tested the Speer Gold Dot 115-grain a while back, and it was a really rather good performer. The heavier Gold Dots hadn’t fared as well from the 3″ barrel, but the light 115-grain bullets did much better. After that test was released . . .
several people asked for a test of the “+P” version. Well, Speer doesn’t make a 115+P… but, apparently, other manufacturers do. Specifically, Underwood and DoubleTap both offer 115+P defensive loads that, while they don’t say “Gold Dot” on the box, they sure do walk, talk, and quack like a Gold Dot. It appears to be a marketing restriction; apparently Speer sells their bullets to other manufacturers for them to use, but doesn’t authorize those manufacturers to use the “Gold Dot” trademarked name. Accordingly, Underwood sells theirs as a “115gr. GD J.H.P.”, and DoubleTap offers theirs as a “115gr Bonded Defense JHP”.
But make no mistake, these are Gold Dots. I wasn’t sure when I started the tests, but one look at the expanded bullets will erase all doubts — these are the genuine Gold Dot bullet.
So both Underwood and Speer offer a 115+P version of the Gold Dot. How do they compare to each other? Is one better than the other? I decided to do a combined test, to answer those questions. And the answer is….
… they’re Gold Dots, loaded to a higher velocity. They perform extremely similarly to each other, in terms of expansion and penetration. The DoubleTap actually clocked in at an average of about 38 fps faster than the Underwood, and both of them showed a notable increase over the Speer standard-pressure load. The Speers, in my test, delivered 1123 fps; the DoubleTaps averaged 1245 fps and the Underwoods averaged 1207 fps. So we’re looking at a speed increase of around 84 to 122 fps faster by going to these +P loads vs. the standard pressure loads. Recoil increases commensurately, as you’d expect.
What you may not expect is what happens with the penetration, though. Both of these +P loadings showed quite a bit LESS penetration through the bare ballistic gelatin than the Speer standard pressure version! Whereas the standard pressure version penetrated to 12.50 to 13.00″, the +P bullets came in at between 9.50″ and 11.00″. That’s 2 to 3 inches shorter penetration. Why? Because these faster bullets used that additional energy to expand to simply gigantic proportions.
The bare gel bullets are massive starfish, as opposed to the standard pressure loadings, which were textbook typical Gold Dots. The standard pressure bullets expanded to an average diameter of .554″, with a maximum size of .646″. That’s pretty big, considering the bullet starts out at .355″ in the first place, so at .646″ the standard pressure bullet expands (at a maximum) to be 82% larger. But the Underwood and DoubleTap speeds push that expansion to behemoth proportions (well, a behemoth of a little 115-grain bullet). The Underwoods grew to a maximum expansion of .787″, and the faster speeds of the DoubleTap had them growing even larger, to .808″. That’s 127% larger than the original diameter — it’s extreme expansion.
But, the more a bullet expands, the less it can penetrate. Expansion acts like a “parachute”, increasing the drag on the bullet as it travels through the gel (or flesh or water or whatever you’re shooting it into). The bigger the parachute, the quicker it slows down. The initial “smack” and the initial temporary cavity are bigger with these faster bullets, but the overall penetration (in the bare gel) is quite a bit shorter than the standard pressure versions.
Surprisingly, in the denim, the faster +P bullets actually expanded a tiny bit less on average than the standard pressure loads did (about .455″ for the +P versions, vs. about .472″ for the standard pressure bullets). I don’t have a good explanation for you on that; the overall size and penetration was generally about comparable between the +P versions and the standard pressure. Penetration was fantastic; the DoubleTaps averaged 15.80″ and the Underwoods reached 16.30″ on average.
Through denim, all three of these Gold Dot variants performed great. Through the bare gel, I would have to say that the standard pressure performed better, from the 3″-barrel pistol. The +P versions weren’t “bad” through the bare gel; they averaged 10.40″ for the DoubleTap and 11.00″ for the Underwood. That’s probably okay, but not ideal; the established standards for bullet performance call for a minimum of 12.00″ of penetration through ballistic gel. An average of 10.40″ is a little short of that, but given how excellent the denim performance was, and that in actual autopsies the recovered bullets generally look more like the bullets recovered from denim-covered gel testing, I’d say you’re probably just fine with the +P versions as offered by these companies.
The question to consider then at the end of the experiment is, is it worth it? What do you really gain by going to the +P version, and is it enough to make up for what you lose? In my opinion, it’s probably not. The higher velocity would give you better performance at long range. But a 3″ pistol isn’t meant for long range engagements anyway, so that’s a moot point. The standard pressure gives plenty of penetration and good expansion. The +P versions give better expansion but even less penetration. And, using +P means more recoil, which may slow down your follow-up shots and means more wear and tear on the gun.
If it were me spending my money, I’d go for the standard pressure Gold Dots and skip the 115+P. If you really want a +P Gold Dot, I got superb results from the Speer 124+P Short Barrel ammo, and I would expect comparable performance from either Underwood’s or DoubleTap’s 124+P versions as well.