I have a Full sized Glock 17 and Glock 22 and I know to switch the Glock 22 to 357 Sig all I need is a barrel.  I am just curious what does a 357 Sig really offer that a 9mm or 40 doesn't?  

My plan is to take my Glock 17 lower and set that up more for target use with a smooth 3.5# trigger, extended slide stop, and a Glock 34 upper that I picked up in trade.  The Glock 22 lower will be used with both the Glock 17 and Glock 22 uppers and it will be mostly used as a HD gun but I do have a couple CCW capable hollsters if I decided I wanted to carry either the Glock 22 or the G34 Want-A-Be.

Now, my primary CCW is a Glock 30 and my wife carries a Glock 26.

I have seen used Glock 31 barrels for sale and I am just trying to decide if there is much of any advantage to having 357 Sig capability....  What does the 357 Sig offer me beyond another round of ammo that I "could" use?

This should help some :D

Nada.

Where do I begin. A .357 sig rnd. is more of a flat trajectory round, It will give you consistency close-up or far away. It works off the same premise as the .223. Small caliber for accuracy lots of powder for distance and penetration. The Feds have spent alot of time researching the data and .357 sig bullets are expensive for a reason you know. They work! I have many calibers in handguns and there is no one perfect rnd. for all situations. I personally like the .357 because it does not have the actual muzzle flip of the .40 cal( a round I respect alot) but it is a loud rnd....I could go on and on about deep penetration, f.t.f does not exist, etc. etc. Hammer over    

Quoted: I have a Full sized Glock 17 and Glock 22 and I know to switch the Glock 22 to 357 Sig all I need is a barrel.  I am just curious what does a 357 Sig really offer that a 9mm or 40 doesn't?

The .40 S&W is a pretty versitile round, and there are only a few things that the .357 Sig offers that you can't find some round in .40 S&W to be compaable to.  

Perhaps the advantage that most will have an interest in is lower recoil than the .40 with bullets that penetrate 12" or more.  The recoil impulse of the .357 Sig with 125 grain full-power bullets is smaller than   the .40 S&W with 155 grain or heavier bullets.  The only .40 S&$ load with comparable recoil are the 135 grain loads which sacrifice either power or penetration.

The .357 Sig is also a better choice than the .40 S&W for applications or risk assessments that involve longer range use or require greater accuracy.  No pistol is a great substitute for a rifle at 50 or 100 yards, but the .357 Sig has a flatter trajectory, less wind drift, delivers more energy and and is more accurate than the .40 S&W at those ranges.

On the other hand, the .40 S&W does have one advantage over the .357 Sig: the ability to load snake shot.

Michael Courtney

Quoted: On the other hand, the .40 S&W does have one advantage over the .357 Sig: the ability to load snake shot.

Well, that and 40 S&W ammo is cheaper and more widely available....

Thanks for all the great advise....  I will need to adsorb all of this and if I find a G31 barrel decide at that point...  If I may also ask, is there an advantage in the 357 Sig if you went to a longslide like a G-35 with a 357 Sig barrel installed?  Given that Glock does not make a long slide 357 Sig might be an indicator that there is not an advantage but I figured it was worth asking.  

I have a G34 upper and I would also be curious if anybody makes a Drop-In G34 barrel for 40 or 357 if I used it on my 3-pin G22 lower?  Unfortionately my G17 lower is 2-pin