S&W M&P .357SIG vs .40

[XGC Radioactive]

Alright, so my carry of choice is the MP.40 (Federal Hydrashock JHP , though I recently converted it to a .357SIG (using Hornady CD JHP). It's working wonders. My groupings on the 357s is a heck of a lot tighter at 25. It's a smaller lead( about a 9mm), but the powder of a .40. Much higher speeds and less drop.

What do you guys think? I mean I carry 15+1, so stopping power doesn't differ much when it just goes "click" at the end.
It was a simple barrel swap, which is made by S&W.

[xb12s]

Carry and shoot what you enjoy and what you shoot best with. Others will chime in to follow perhaps with some links, but there are loads (see what I did there) of caliber war threads all over the net. After reading a bunch of those for years I found some newer, statistically-supported research that suggest that new hollow point ammo is basically as effective (translation = not that effective) for defense in 9 thru 45. Expansion is better than ever, more predictable, etc and penetration is good enough for 9, 40, 357Sig and 45. Look around for a good load/manuf in the caliber of your choice and you will be in good shape. If carrying a larger caliber over a smaller caliber makes you feel better, that's okay too.

Let me explain the "not that effective" comment. Most people survive gunshot wounds. Basically, the size of the projectile when expanded is not too big, so shot placement is quite a bit more critical. That and hoping the psychological effect that being shot will make most people want to lie down. A rifle or a shotgun is better still, but it's hard to conceal those in my waistband. Maybe if I wore a duster...

I have an M&P40c, and have a 9mm conversion bbl, but not the 357sig. I carry it in 9mm sometimes (more than 40 honestly), because I shoot the 9 better. I still have an interest in picking up a .357 Sig bbl for one of my full size guns, but not my compact. For me, I will probably never carry that way, but I like having options and its fun to shoot different things sometims.

ETA: I kinda got derailed on caliber discussion. Sorry about that. I think it's pretty cool that your groupings tightened up and that's a neat discussion on it's own. Hopefully someone else can chime in with similar or differring experience. I've only shot a .357Sig from a SigP226, and never compared it to same size/dif caliber gun. I felt that the P220 handled 45 with less snap. The P226 definitely handled the 357 Sig better than my M&Pc handled the 40, but those are two different animals.

[jayinsat]

I don't see how you guys can afford shooting the expensive defensive ammo so often. I carry Hornady CD .9mm. I shot about 10 rounds of it to get a feel and won't shoot any more. I just recently bought another box to replace the ones i've taken out of rotation b/c of bullet set back.

I practiced with some Winchester 115 gr jhp and federal 115 gr jhp. I have a few boxes of that to carry if I can't find or afford the Hornady.

[TexasCajun]

I wouldn't trust my life or that of my family to a conversion. The S&W forum has enough .40 conversion threads to lead me to believe that it's safe enough for the range, but most use the original barrel for carry / HD. I'll eventually get the 9mm barrel & mags and .357 barrel for my M&P .40. But like others, that will only be for the range.

[CC Italian]

.357 sig. Or. 40 s&w doesn't matter. I think the extra speed over 9mm + p is no difference Imo. Some say the penatration of the sig is better but it isn't needed Imo. Plus if you want a deep penatrating 40 in a jhp just get some of those 200 grain noslers. In the end it is still a heavier bullet with a larger diameter. Shoot what you like.

[XGC Radioactive]

I wouldn't trust my life or that of my family to a conversion. The S&W forum has enough .40 conversion threads to lead me to believe that it's safe enough for the range, but most use the original barrel for carry / HD. I'll eventually get the 9mm barrel & mags and .357 barrel for my M&P .40. But like others, that will only be for the range.

the conversion is simply just dropping in a new barrel. The mags are the same. a 357SIG is litterally just a .40 shell necked to a 9mm lead.
400 rounds through the conversion and not a single missfire.
more than 1000 .40 rounds through it as well.


now I wouldn't trust it to an aftermarket swap, but the barrel I bought is a OME.

[XGC Radioactive]

I don't see how you guys can afford shooting the expensive defensive ammo so often. I carry Hornady CD .9mm. I shot about 10 rounds of it to get a feel and won't shoot any more. I just recently bought another box to replace the ones i've taken out of rotation b/c of bullet set back.

I practiced with some Winchester 115 gr jhp and federal 115 gr jhp. I have a few boxes of that to carry if I can't find or afford the Hornady.

when I try out a new defensive ammo, I shoot ATLEAST 3 boxes.

I want to make sure my gun will eat it.
I bought the stuff before the hording, so like $23ish a box.

[CC Italian]

The only real benefit of the sig is the bottleneck round Imo. Supposedly it helps with ftf but I have over 10000 rounds on a glock 27 witthout a single ftf so i don't know how you improve on that. Imo if you want a more powerful semi auto step up to the 10mm or 460 Rowland but this rounds are better only if you handgun hunt otherwise. 357 sig. 45 .40 9mm. It isn't a big enough difference as people want to make you think.

[xb12s]

I'll have to take a look on the Smith or MP pistol forum regarding conversion issues. I'm intereseted. I've had no issues with mine with over 1000 rds. Not saying it's not a real issue, it most certainly is or could be. Depending on what I read about it, it might change my mind about carrying it. Regarding the other comment made about trusting the Smith barrel, two things -- I agree, the 357 Sig barrel is just a drop in Smith barrel so it's not like you're actually changing the gun.

I'm interesting in what brand barrels had issues on the Smith forum. I have a storm lake. The quality seems top notch. My original OEM Smith 40 barrel had to be sent back to have the feed ramp polished. This was in the early days and they fixed that issue since then, but I wasn't alone in that issue. I had considered switching to 357 Sig at that point because it feeds better by design. Then cost and recoil in shooting it in the compact frame dissuaded me.

[68Charger]

Just price wise, the 357Sig is so darn expensive, it's ridiculous. I barely shoot my P226 in 357Sig because of cost. The 40 is more readily available, in my case. It seems as if there aren't enough people who carry the ammo, or their prices are ridiculous. Though, your mileage may vary.

[cbunt1]

Personally, I agree with carrying and shooting what you like. The barrel replacement/caliber conversion is nothing to worry about, especially running .357 SIG in a gun originally chambered for .40 S&W -- they're dimensionally identical, at least from a feeding perspective.

Ballistics-wise, I've always considered the .357 SIG to be identical to a .357 Magnum revolver -- 125 grain bullet traveling about 1300 FPS is a standard SD load, and it's a proven time-honored "man stopper" in the old .357 Mag cartridge...so you're in good company with a good history.

The Texas DPS carries .357 SIG as a duty/issue round, and has had great success with it.

Frankly, the only reason I don't own one is that I haven't stumbled across the right gun or barrel conversion at the right price at the right time. I was never a fan of the cartridge for someone who strictly shoots factory ammo, just because of the price, and as a reloader, it presents all the headaches of a bottleneck rifle cartridge, and the brass is comparatively rare (i.e. I can pickup up 9mm, .40, and .45 by the bucketfull with no serious effort--.357 sig takes a while to amass a collection of brass).

Why the ammo is expensive? You got me. From a factory production issue, I'm sure it's a little more costly just because the brass is a bit more expensive, but the first loading of virgin brass should be nothing more than any other cartridge. The bullet isn't "special" -- it's a 9mm 125 grain hollow point, and the powder charge is comparable to other defense-level rounds...and several major departments use it, so it's not "rare" in that sense...

But it is expensive to shoot. Not prohibitively so, just irritatingly so. Great round. And if you shoot more accurately with it, that's always a good thing. In the caliber wars, my mantra is "shoot what you're most comfortable with, and most effective with" and forget what anyone else has to say about it....

[Pecos]

Thats a fine gun but everybody is right. Very expensive. I carry the G17 gen4 (CD Ammo). Less recoil help me stay on target easier. In a stressful situation that will help me.
It's like every one says it's what works best for you. I be doing a lot of dry fire training if I had the .357. Heck! all ammo is too expensive lately!

[cheezit]

one of the reasons i like the 135gr 40. round

[jmoney]

I'm curious as to why you feel the need to switch to 357 sig. I see these caliber debates all the time, but at the end of the day its shots on target that really matters. If you shoot the 357 better under stress, then go for it. I used .40 cal forever until I took some real training courses. I moved to 9 and I won't look back. I was more than accurate with the .40cal, but I put many more shots on target in less time with the 9mm. Plus I can reload and train with 9mms at a much lower cost.

[docbrazos]

I'm curious as to why you feel the need to switch to 357 sig. I see these caliber debates all the time, but at the end of the day its shots on target that really matters. If you shoot the 357 better under stress, then go for it. I used .40 cal forever until I took some real training courses. I moved to 9 and I won't look back. I was more than accurate with the .40cal, but I put many more shots on target in less time with the 9mm. Plus I can reload and train with 9mms at a much lower cost.

Every body has their own opinion but Jmoney is stating fact from his point of view. (which I sure don't disagree with.) personally I like the 357 sig and it was my first (of many Glocks) but it has long since been converted to ammo easier to come by.............. 40 and 9mm for daily carry!