Reduced power 10mm loads for self defense

[corneileous]

I’ve read about it in places like lucky gunner and on other forums but is it true why a lot of your store-bought 10mm self defense rounds are reduced in power than a typical full-power 10mm? I’ve also heard that the ammo companies that do this either don’t know what they’re talking about- which is weird, or that they do it to cater to the people who probably shouldn’t have a 10mm in the first place.

Being that I bought my Sig P220 10mm Elite for woods carry, at one point before I had heard this about reduced-power ammunition and when the pistol was just at home for home defense, I’d just have it loaded with those 185g Sig V-Crown hollow points because at the time and without putting a whole lot of extra search into it, those were like the only full-power rounds that were coming up so those are the ones I chose.

For that pistol, if I was to load it up for home defense, those rounds I bought- are they the better choice or would I be better off to get what most of the major ammo manufacturer’s say a self defense round for a 10mm should be?

Thanks.


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[DocGKR]

A short answer is that a reduced power 10mm load is called .40 S&W.

A bit longer answer is to look for ammunition that is reliable and accurate in your pistol; that meets standard terminal performance guidelines (ex. 12-18" penetration, barrier blind with robust expansion) as outlined by organizations such as the FBI BRF, JSWB-IPT, CTTSO-TSWG, IWBA. Note that nowhere do valid requirements speak of "full power" or "reduced power"--it is all about measured quantifiable performance. In addition, for defensive/duty ammunition it is desired that the ammo vendor has experience producing product under strict USG contract and quality control guidelines.

[corneileous]

I figured a reduced-power 10mm is pretty much essentially a 40S&W in a 10mm casing but I guess what I’m really asking is why are there even reduced power 10mm’s in the first place? Why do some ammunition companies choose to do this?


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[Bergeron]

I respectfully disagree with the idea that most 10mm loads are reduced power. My own personal (and limited) experience is that it’s easier to find the full power stuff, and that reduced power loads are the challenging ones to find. To re-post an exercise I went through a few months back, here’s what I found out on the 10mm market:

Going down the list, we have:

Blazer Aluminum, 200 @ 1050, 210 PF

Hornady Hunter, 135 @ 1315, 182 PF

Winchester Silvertip, 174 @ 1200, 210 PF

S&B JHP, 180 @ 1164, 210 PF

Blazer Brass, 180 @ 1200, 216 PF

Federal HST, 200 @ 1130, 226 PF

Armscorp JHP, 180 @ 1008, 181 PF

Privi Partizan JFP, 170 @ 1115, 190 PF

PMC JFP, 170 @ 1200, 204 PF

Hornady XTP, 180 @ 1275, 230 PF

Magtech FMJ, 180 @ 1230, 221 PF

Magtech JHP, 180 @ 1230, 221 PF

Federal Trophy Bonded, 180 @ 1275, 230 PF

Speer Gold Dot JHP, 200 @ 1100, 220 PF

Barnes TAC-XP JHP, 155 @ 1150, 178 PF

Federal AE JFP, 180 @ 1030, 185 PF

Fiocchi FMJ, 180 @ 1275, 230 PF

Winchester FMJ, 180 @ 1080, 194 PF

Recall that USPSA Major Power Factor is 165, and you can see how powerful a lot of these loads are.

My own, limited thought, is that the bullets are designed for specific velocity ranges, and a “mid-power” .40 expanding bullet needs to operate in those middle velocity ranges for best effect, while a .40 bullet designed for “full-power” similarly needs those higher velocities to perform as designed.

My preference for 10mm self defense against people is for modern bullets in “.40 S&W” load levels, and I also prefer that load level for USPSA. My preferences change for uses like bowling pins, medium game, or other “field” uses. For me, the charm to the 10mm is its ability to cover both bases.

[Duelist]

Not every round fired through a pistol has to be at the maximum, highest performance level. This is shown from .38 SPC Match Wadcutters through .357 Magnum loads that are barely hotter than +P .38 loads up through 180gr .357 bear hunting/metallic silhouette loads, and on up through the biggest rounds. Cowboy action .45 Colt rounds, for example, run through .454 Casull revolvers and make a more pleasant shooting day where Casull level loads aren’t necessary or appropriate.

If you want to run full-power woods loads through your 10mm all the time, go for it. Probably will have to replace your recoil spring a little more often, but that’s hardly a big maintenance expense.

[Trooper224]

I remember firing the otiginal 10mm loads through the Bren Ten and the early Delta Elite. That wasn't anything I wanted a full diet of, even then.

Gauging how powerful a load really is by using gamer power factor rules is a bit of a strawman process.

Remember, there's been a lot of development in projectile design since the 10mms introduction. Muzzle velocity is no longer the only predictor of power and performance, expansion and penetration are. Neither of these are still totally dependent on muzzle velocity. Using hot mancard qualifying loads for self defense really isn't necessary, where as something heavier would be desired for wildlife management. A wide spectrum of loadings is one of the attractions of a round like the 10mm.

[Bergeron]

Yes indeed, and my only intention in listing power factors is to give a sense of how the recoil compares. While I totally agree that power factor and terminal ballistics are entirely separate things, I also find it to be a good way to compare recoil.

I've shot USPSA and Steel Challenge with 200+ PF loads. It's fun to do occasionally, but the score does suffer.

[corneileous]

So as long as it shoots and cycles well, it doesn't really matter what the muzzle velocity or energy is? As I was saying before I even new anything about it when I first heard about some 10mm loads supposedly being less-powerful than others, I figured that since I bought a 10mm, I didn't want "watered down" ammunition for it and when I was shopping for self-defense/home-defense ammunition, I settled on the 180g Sig V-Crown instead of the Speer Gold Dot or the Federal Premium HST because the V-Crowns were 1250 fps whereas the HST's are 1130 fps and the Gold Dots are 1100 fps. I guess I didn't take into account that maybe the reason the V-Crowns were faster is because they're 20 grains lighter than the other two.

[Bergeron]

I think it'll be difficult to get a better answer than the second post.

Ammo that functions the gun well, that is accurate, that meet standards of penetration, expansion, and barrier performance produced at USG contract quality- I don't know what else would matter.

Gold Dots and HSTs are popular with law enforcement.

[DocGKR]

V-Crowns are generally offer poor intermediate barrier performance and would not be a good choice for defensive or duty use.

Both HST and Gold Dot are better designs.

Velocity and "Energy" are not wounding mechanisms, so are not useful measures of terminal performance.