I'm looking to get a cx4. I'm a big fan of 9mm for pistols as well as .45. Don't like .40 much. It makes more sense in a carbine to me because it'll eat recoil. So 9mm or .40? Pros and cons of each for this platform.

9mm for price and those g18 mags.
But, I must say me and a few other guys were amazed by the recoil of my storm in 9mm. I imagine 40 would be enough to give you a twich at trigger time.

G18 mags in a Beretta?  No, don't go down that road....the CX-5 Storm uses Beretta magazines!

I like the 9mm...and have owned once since they first came out. Why 9mm?  

Ammo cost and availability

Magazine availability (especially if you get the one that uses the "92" series magazines. They are available in a  Hi-Cap 30 round magazine. My personal favorite however is teh MecGar 20 round mag that fits flush up in the grip.

Perceived recoil. on the 9 is sharp. That is common on most if not all blow-back firearms as the big heavy bolt hits the back of the receiver. I can only imagine that the 40 has to be much worse.

Get the 9.  92 mags are much easier to find than 96 mags.  And PX mags are stupidly expensive, and nobody likes them unless you have a PX4....which you'd have to sell as a set if you wanted to maximize resell value, because everyone wants the 92 mag version.



Don't forget to pick up a 92 while you're at it.



 

9mm is the most common caliber in Storm carbines, that what mine is. I have a few PCCs in 9mm & .45acp since that's what my handguns eat, and I've been tempted with a carbine in .40 S&W as it would seem to shoot flatter than 9 or 45, but I don't have any handguns in .40 so it just doesn't make sense to stock up on another caliber. A storm .40 would probably be a good choice for target shooting at 100 yards and would have more punch for home defense but I think the best argument for the 9mm platform is the inexpensive factory 30 round magazines.

What a sweet shooting/accurate carbine Beretta made. Mine shoots perfect and it is nice to have a carbine you can swap mags with a pistol.

So, if I read all the comments here I come to the same conclusion I did many years back when I bought my Storm (when they were a new model). The 9mm is the most practical for general use...range plinking and home defense. If I were really going to use it for something like hog hunting (and they are good for that) or had a pistol that used the caliber a .40 might make sense. Otherwise, 9mm is the most common and for good reasons.

My bad; thank you forever4! I was thinking of the JRC.

As has been said, it's CX4, not PX4!

I like multi - tasking items and since I have a butt load of 9mm and already had a 92f it was a no brainer . I really havent done alot of experimenting with the storm . it worked great from the very start , and I believe in if it aint broke then dont fix it . I have no regrets in my purchase .

Man you are so overstating the recoil of 40 cal.  It's a carbine for Pete's sake.  Recoil of the forty is nothing.

Doc

At the range on Friday and a guy next up from me was talking about how he wished he had gotten his new CZ P-07 in 9mm and not .40. It said he could shoot much better with the 9 as the .40 was "snappy" and that he could do much better follow up shots with the 9mm which had less recoil.

While some people for whatever macho reason feels the recoil of a .40 is "nothing", others find it distracting and not helpful to accuracy for quick follow up shots.  I have seen some that just couldn't put a second shot on the target quickly as they fought hard to overcome the muzzle flip of the "low recoil" of the firearm. Recoil is in the users mind and they should make the decision on what they feel comfortable with.

9mm

"Macho" has nothing to do with it.  It is my 11 yr old daughters favorite rifle.  It is a pistol round in a carbine.  If the recoil of a forty caliber bothers you in this rifle, the nine will be little better.

Ymmv

Doc

I have not fired a 40sw carbine.
Ended up getting the 9mm/92mags, because I already had a m9. Mags are cheaper than other option, even better when you can find surplus. I already had 9mm ammo.
Nothing against 40sw although I do not own a gun in that caliber.
I wouldn't really worry much about the recoil aspect the 40 will be more than 9mm. But I believe most of the recoil comes from the bolt hitting the back than from the round firing. It's sort of strange like a delayed recoil from the time it takes the bolt to come back.
I really only have about 600 rounds through it so far I love it, the girlfriend love to shoot it so that makes it even better. I would go 9mm again if I was doing it again.

That's a pistol, way different.  I have a 40s&w one and the only drawback is the mags to get a good amount of rounds in it.  I can put as many rounds down range as I want without fatigue or flinching.  I do reload 40 for a few guns, so ammo is not an issue.  Mine does have the reliability mods and a trigger kit in it, and is one of my favorites.  Except for the mags for the 40's.

Well, not exactly. While some find a 300 WSM or a .308 recoil to be "acceptable' others do not. Personally, even after many (and I do mean many..as in decades) of shooting I have covered a large range of firearms and recoils.   When I started shooting 9mm carbines I thought they would be "recoil free" with that puny pistol round in a "rifle". Not so it seems. I really feel, like many, that its more the perception of recoil that we feel. The blow back action pounds that bolt back into the back of the receiver and you feel it hit hard. It makes you think there is more recoil than what there is.  In shooting my diverse group of 9mm carbines/rifles I find there to be a somewhat sizable variation it their perception of recoil. It appears to be greatly related to the weight of the recoil spring, the mass of the bolt, the weight of the rifle, and the quality of the buffer mechanism. We all know the actual physical recoil force should be the same (that's simple physics) but in practice the perception of recoil is widely different in these rifles. It then stands to reason (that physicas stuff again) that the .40  in a rifle or pistol, will give more "snap" to the feel. I would recommend that if one wants to decide the very best way is to go out and shoot both. No, not two or three rounds but a good sample run on one. Different positions, rapid and slow fire, etc. You be the judge

The pistol example was simply to show that between two rounds the 40 has a lot more snap to it.  

I have one in .45 ACP, and if I were to do it all again, I'd definitely go 9mm...

Got one in 9mm that takes 92 mags. One of the best purchase in my life.

I just bought a CX4-9mm yesterday that  does not take the 92 mags. I found that you can get magazine conversion kits so that it can. Already have one ordered. Only reason I got the one that doesn't take the 92 mags is that this was the only one in town and I didn't want to mess with transfers and gunbroker, etc.

9mm

9mm.

FACTORY 30rd mags.

Need I say more?