40 cal.+P as good as 10mm?

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Looking at the data (mostly acquired from the Buffalo Bore website), I don't see a whole lot of difference when using a 180 bullet. I recently purchased a 40 cal., and while I shoot it well enough, I am feeling the 10mm tickle that I'm sure strikes all shooters eventually. Buuuuuut...

is it worth grabbing one if I can run similar ammo through my 40? Thoughts?
 
Looking at the data (mostly acquired from the Buffalo Bore website), I don't see a whole lot of difference ...

.40 S&W +P (I don't believe there is a SAAMI +P .40S&W) https://www.buffalobore.com/index.php?l=product_detail&p=117
- 180 gr at 1,100 fps for 484ft/lbs

10mm https://www.buffalobore.com/index.php?l=product_detail&p=114
- 180gr at 1,350fps for 728ft/lbs

That's an extra 240 ft/lbs out of the 10mm. I think that's a pretty decent increase in power for the 10mm.

In addition, the 180gr is about as heavy as the .40 S&W can go, but the 10mm can go up to 220gr.
 
Yeah, there is no such thing as 40SW +P, and the Buffalo Bore site is definitely not a place I'd go for any reference to load standards. Can you load any cartridge you please to 10% over the standard pressure and call it +P? Sure you can. And if you don't measure your pressures and take the *statistics* associated with those measures, you can load to 12% or 14% above the recommendation and call *that* +P, too. Heck, folks sometimes refer to 10mm Auto +P, too, and 10mm +P "is not a thing", either. I've always felt 180 gr was already pushing it for 40SW anyway--there's very little wiggle room there in seating depth without potentially moving peak pressure a lot further than you maybe think you are.

The sweet thing about 10mm, IMO, is you can load it *down*, reduce pressure, and get 40SW "+P". That's a direction you can go and not worry if your firearm was built to take it...or not.

Since there IS no 40SW +P recommendation, to me that means no manufacturer of 40SW-chambered firearms has wrung their products out for 40SW +P use. Of course we assume all major manufacturers know about safety factors and overbuild to accommodate variation in ammo. It's the allowable variation that SAAMI helps to define, and in part that's why SAMMI exists, why standards exist, and why folks might choose to comply with those recommendations--to specify what that variation can/should look like. Offering such a product with such a label in the first place (a 40SW +P) is further confirmation, to me, that certain ammo manufacturers don't really give a hoot about complying with those standards or supporting them in name and deed. Just my opinion.

As for "is it just as good"...I think the question is "can I get a 180 gr bullet to go about as fast?". I can safely load a 9mm Luger bullet to "go just as fast" as comparable bullet can be safely loaded in 10mm Auto. One at the high end of published loads, the other at the extreme low end of published loads. Is one just as good as the other? Are they comparable? I think it all depends on your personal definitions of comparable and just as good.
 
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JTQ and Bongo Boy have excellent points.

I do not own a 10mm...yet. It’s coming.
But, I learned a long time ago by watching the mistakes of others that hot-rodding a round might look good on paper and yes, it is doable, but at what possible cost?

I tend to shy away from exceeding the limitations of a device that I hold in my hands and put in front of my face that ignites a concussive force when I activate it.

I know it’s often easier said than done but if you “need” a 10mm, buy a 10mm. Trying to make a .40 S&W do 10mm things may not go well and you may be in the market for a new .40 as well as a 10mm...hopefully sans medical bills.

My 2 cents
 
The reality is we don't know if it is actually and "better" for any practical purposes, but 250 more ft lb seems significant to me.

In my experimentation the true joy of 10mm is the 200 grain bullet at around 1200 fps, powerful and very shootable (I can run it pretty much like .45 in a 5" 1911). With XTPs it gets some expansion and deep penetration, ideal for a woods gun that might (possibly, buy very unlikely) need to fend off a black bear. The hard cast loads at the same weight and speed are excellent as well.
 
When I was working on a load for my M&P 40 I found it shot better a little less than max with the 180gr bullets and at less than 25yrds even liked them on the low side, at a little over 25yrds they were more like a shotgun (could have something to do with the trigger finger :))
 
They are both "good" in the sense that they are powerful rounds that will do their intended job, which is to put down an adversary. That said, of the 2, I would prefer 40 for the typically smaller and lighter handgun as compared to a similar design in 10mm, along with the economic factor and availability of ammunition.
 
In cars, the old adage is "there's no replacement for displacement." Similarly, in straight-walled pistol cartridges loaded to similar peak pressures, case capacity is a thing. The 10mm loaded to SAAMI length has more case capacity than a .40 loaded to SAAMI length.

Now, if you load 40 to pressures past SAAMI, and keep 10mm within SAAMI, sure, you can equal the 10mm... right up until you either blow up your gun or you let the same amount of leash out on the 10mm. Similarly, if you load .40 long to the same overall length as 10mm, you can duplicate 10mm loads in every respect... but those rounds won't chamber in a standard .40-chambered barrel, and won't fit a .40-length magazine.

It has always surprised me that reaming the barrel of a .40 to have the throated length of a 10mm but the headspacing chamber of a .40 isn't a common customization. With bullets on the heavier side (180 and up) you should have more than enough bullet/case engagement to avoid setback.
 
if you “need” a 10mm, buy a 10mm.

And in most calibers I'd absolutely agree with this. I dont get +p or +p+ ammo. Especially in a young caliber. that said, some 10mms cant handle 10mm any better than some 40s would. I've personally had not one but 2 newer 10mms blow cases with 10mm ammo that was factory loaded to hot 40 specs. On one occasion I was shooting through a chronograph, I know the round was in spec. (And no, neither was a glock) I own more 10s and 40s than all other calibers. More so now than 2 years ago, With the low prices of trade ins in 40 (G22, G27, 226, 229, 320, all 300 bucks truly is crazy to me. and usp for 350-400). The case support on some, combined with junk brass has caused many issues in 10. My Usp or 226s arent chambered in 10mm (although one 220 is) but I have zero doubt they would handle hotter 40 than my deltas or kimbers would in 10mm.
 
The case support on some, combined with junk brass has caused many issues in 10.

Ayup. Anyone looking to shoot "real" 10mm needs to pay close attention to these two factors. Total recoil forces of 10mm aren't that different than full +P .45 ACP, but the case pressure is quite a bit higher... so you can't get away with nearly as much brass "showing" around the chamber. And you certainly can't do that with soft or brittle brass.
 
Creston, which brands of 10mm brass do you consider junk?

Armscorp and amerc are known junk. I scrap all of those and won't even use even factory ammo in some guns. I've re- loaded starline, Remington, hornady, ppu, winchester, Norma, many times up to the magical 200 grain at 1200 fps.. with all the big name brass with no issue. In many 10mms though the brass will bulge even at 40 velocities in some chambers. 1911s are known for it. My glock 29 bulges more than I think it should but my 2 glock full size guns have support, as well as my Kkm match 6 inch. I can shoot that armscorp in the 29 without it blowing in it so it has more support than some but not great. If I'm shooting my better supported guns somewhere that I know I cant find half my brass (much bigger issue in 10mm than some calibers btw) I shoot the armscorp but I'll make sure to never get it again if I can help it. The only reason I got it in the first place was that I shot many cases of BVAC ammo which came in starline cases. Great ammo and great price Then one day my bvac came loaded in armscorp instead of starline. First clip in my Delta blew 2 cases shooting through the chronograph (180 gr at 1100ish IIRC). I contacted BVAC. They blame the gun although I can shoot factory norma 200s at 1200+fps in the same gun.... but they sent me more ammo......hollow points loaded even weaker and still in armscorp brass. No knock on BVAC but they had some junk brass. I havent bought from then since (because I havent needed to, not because I'm boycotting) but I'd guess they ditched armscorp.
 

PPU 10mm is actually in my suspect category. I accumulated a lot of it before I started reloading (10mm PPU was the cheapest factory ammo at the time and I shot a lot of it and kept the brass). It works great... right up until it gets work hardened and loses all neck tension. I had some big-time setback issues with it. One scary incident resulted before I diagnosed what was happening. If you're running PPU multiple times, be sure to check setback/tension on every round.
 
PPU 10mm is actually in my suspect category.

I only load full power loads in new brass with hand weighed charges on my single stages in 10mm. Mostly because of the variety of guns it may be fired in. Mostly starline or hornady brass. I throw the rest in the progressive press hopper and load up my lighter 180 grain lead/plated plinking load with unique. I havent had a ton of ppu but no issues either. Some of my guns are rough on case rims so they usually get lost or break pieces of the rim and get trashed before any problems.

In bottlenecked cartridges I'd add Nugent brass to the bad catagory. I've had case necks split on the first resize. Remington 300 mag brass seems to have less life than many as well. More like nickel plated brass than normal brass but I wouldnt say its bad.
 
It has always surprised me that reaming the barrel of a .40 to have the throated length of a 10mm but the headspacing chamber of a .40 isn't a common customization.
That was actually pretty common in USPSA back in the ‘90s when everyone was shooting 200 and 220 gr. bullets long-loaded in .40 cases. They were super soft shooting.
 
I've probably loaded more 40SW than anything else--well maybe more 45 Auto--but let's just say a boatload. I like 40SW and have found some very accurate loads for the SW MP Pro Series gun. It's a cartridge that, to me, can easily outperform 9mm from a ballistics perspective and makes it a worthwhile alternative to that most-popular round. So, I just personally like to take advantage of what the 40 has going for it, and find that sweet spot--which I have never found to be at the high end of book loads. But, I think it's often true that no cartridge does its best at the extreme ends of the load spectrum--maybe a generalization with many exceptions, but my limited experience says pushing anything doesn't result in consistency. We may have beaten this horse, but my preferred perspective of the 40's capabilities would be "bigger than a 9 but not a 10" :).

A bit off-topic, but related to those 200 gr USPSA loads--I remember the fun of sizing monster cast bullets intended for 45 Colt for loading up 45 Auto IDPA rounds with tiny little charges of Nitro 100, Solo 1000 and Clays. Those worked well and were good for a big chuckle. It seemed like you could use a stopwatch to time how long it took to hear the 'doink' when they finally hit the plates.
 
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I found these two videos to be interesting, especially the clay video. Both rounds have solid performance. But I still bought a new 10MM...:thumbdown:




 
Big 10mm fan here.

But it depends on your goals. If you are carrying a handgun to protect yourself from 2 legged predators you don't need a 10mm, nor the hotter 40 S&W loads. I don't have an issue with BB, Underwood, or Double Tap calling them +P even though that may not be technically correct. I've seen nothing to indicate that standard 40 S&W loads or the better 9mm loads are at any disadvantage when it comes to stopping humans. I'd recommend,and actually carry a much smaller, lighter recoiling pistol in 9mm for those situations, or a 40 if it makes you feel better. And I'd stay with standard power loads if I used 40 S&W

As much as I like my 10mm pistols they are the ones I carry when hunting/hiking/camping in bear country. The hotter 200 gr loads @1300 fps have stopped brown bear attacks and hunters have used them to take game as large as cape buffalo. Unless you want to specifically buy a 10mm for large predator protection then I'd stay with the 40 you have.

FWIW I used to carry a G23 loaded with the hotter 200 gr loads @ 1100 fps you referenced. But I eventually traded it for a G29 in 10mm. The gun is the same length/height. but just a bit thicker. I picked up 200 fps with the 10mm. This was my reasoning. Almost all of the manufacturers pistols in 40 S&W have shown more wear and had more issues than those manufacturers same pistols in 9mm. Even standard 40 S&W loads have proven to be hard on pistols. I just didn't trust the hotter loads in a 40. The big frame Glocks however in 10mm and 45 have earned a reputation as tanks that will handle the hottest loads in either caliber and keep chugging along.
 
"They are both 'good' in the sense that they are powerful rounds that will do their intended job, which is to put down an adversary. That said, of the two, I would prefer 40 for the typically smaller and lighter handgun as compared to a similar design in 10mm, along with the economic factor and availability of ammunition."

That's pretty much what I think, too. For poking holes in likely things I might want to poke holes in (paper, plinking objects, and the vast majority of varmints) 40 is more suitable.
 
Trying to push a cartridge past what it is designed for is stupid. If you want to get 10mm performance, then go buy a 10mm pistol.
 
Wow. Just WOW on this good information - especially the first hand stuff! I guess I didn't realize there was no such thing as a true 40cal +P, and I see where it could tear apart a pistol. I'd be sending these rounds through my Sig p229, and if I blew him up I'd never forgive myself.

As far as the Glock 29 goes (probably my most likely option for a 10mm), does the lighter polymer frame make the gun a pain to shoot? I've honestly never shot a 10mm...I just like the allure of the 10mm's reputation.
 
As far as the Glock 29 goes (probably my most likely option for a 10mm), does the lighter polymer frame make the gun a pain to shoot? I've honestly never shot a 10mm...I just like the allure of the 10mm's reputation.

I am very much a proponent of steel frames for almost all cartridges, but I have to say every time I have shot a G29 I have been pleasantly surprised. I wouldn't shoot it much for pure enjoyment (I like big, heavy, steel-framed pistols for actual shooting), but it's nowhere near as painful to me as, say, .357 out of a J-frame. The flexy Glock frame and the wide backstrap do help quite a bit to avoid pain during recoil. That won't help with making rapid, accurate shots after the first shot, but it does mean it doesn't affirmatively hurt to shoot.
 
IMHO 10mm is the king of auto loaders (bottom feeders). Yes, certain semiproduction conversion type calibers do more but if you want an off the shelf normal SAAMI spec'd cartridge that you can easily get ammo for it's pretty hard to beat (i don't include the desert eagle). 40 S&W can do a lot, but keeping up with a 10mm is something that it just can't do safely. I carry my g20 anytime it's cool enough for a jacket, for hiking/camping i do 200 grain fmj or 180 grain jhp and when loaded for 2 legged snakes i use 165 grain jhp gold dots from underwood. Pretty versatile cartridge, you should get one.
 
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