I think I'd like to get a carry gun in this caliber however I have been told by a few folks and read online that the extra slide velocity batters the gun and leads to premature part breakage.   Is there any truth to this argument?   Seems like internet hearsay but I don't want it to crap out after 3000 rounds.   On a side note is .357 sig plinking ammo "downloaded" like some 10mm?

Any input from owners with a high round count would be appreciated.

No issue at all with Glock or Sig. 

With the modern 9mm, there isn't really a reason to shoot or carry .357 Sig, unless you are in love with it. 

I got a 5 gallon bucket of once fired free brass when a LE agency transitioned back to .40, so I load my own.  The blast is excellent at the indoor range and works great to make the place less crowded.

It is not a big problem, but anytime you increase the slide velocity, you will be that much harder on the gun.

I would also expect a 357 SIG barrel to literally wear out before a 9 or .40 barrel.  But, they will still last a long, long time.

I have only clocked a single brand of 357 SIG practice ammo, and it was loaded slightly lighter than the JHPs I clocked that day.  No guarantee that will be so for all brands, however.

It is not some thing I worry about.  A big statistic investigation would probably show that 357 SIG is some what harder on guns, but I would bet that it would not be a very significant amount.

I lost track of how many rounds I have through my G32 that I have been shooting / carrying since like '01 (stopped counting after about 5K rounds years ago).  Barrel still looks / performs as great as ever.  I did stone the top of the locking block down to prevent peening on the bottom of the slide rails when the frame flexes during recoil not long after I got it (which worked) and I have a 20# or 22# recoil spring in it.  No issues.

My Sig 1911 also in 357sig only has about 900 rounds through it so far, also no issues.

10k on current gun. Almost 40k on previous gun. No major issues. Sig P229.

Never broke anything on either of mine (Glock M31 and M&P FS).  The M&P would break batteries in the TLR1.  Light would stop working, pull the batteries and shake them and one would rattle.  Replace that one and the light would work again, till another battery broke (just a matter of time).

I don't shoot either one anymore.  Neither are as accurate as my P07/P09 in .40 S&W or the P09/P01 in 9MM.

Someday, if I find a .40 S&W CZ75/SP01, etc. at a gun show I might get it and get a .357 SIG barrel rechambered for it.

YES!