I used 124 grain SPEER LAWMAN for the first 300 rounds, then I used 147 grain SPEER LAWMAN, around 250 through each of my P320s and P365s. 500-600 rounds on the first range session for each. Make sure you clean and re-lube it first. I normally like to run it "wet" on the first session. Might get a little smokey! LOL

 

What is the gun’s intended use? That model is most often a competition gun, but what are your plans for it?

 

Home defense primarily.

 

It's not uncommon for people to ask about ammo suggestions for a particular new pistol, but having broken in a LOT of new pistols over the years, I can say from personal experience that ammo type is not really that critical for just training. It's only when defensive/carry ammo is at issue that the question becomes more relevant.

For just training, any 115 or 124gr FMJ from reputable manufacturers such as Blazer, PMC, Lawman, CCI, Selier & Belot (S&B), Fiocchi, Federal, Parvi Partizan (PPU) and Remington, among others, will do. These are the most common reputable brands. I've bought thousands of rounds of all of these primarily based on what's on sale at SG Ammo, and I haven't found any to be particularly more accurate than the other in multiple pistols from pocket pistols to full-size pistols.

Aside from the aforementioned manufacturers, I've also had great experience with the 1500-round loose packed LAX Ammo 9mm FMJ ammo.

 

Thank you very much. I appreciate the time and thoughtfulness of these replies.

 

FWIW, my X-Carry took 200 rds before it would function reliably with a suppressor. After that, she runs perfectly with any ammo.

 

I am partial to Fiocchi and Sellier & Bellot. They are true copper jacketed projectiles, not electro-plated. And, they're a little spicy, with Fiocchi 115s coming out around 1200fps, and S&B 115s close to 1300. My P226 X-Five Legion and Staccato XC love them both.

 

When I get a new "9" I like to get a full case of whatever I can get the best price on ... use it for a good break-in and lots of practice. I've never seen a big difference between 115 and 124 FMJ rounds ... it's only 9 grains. 115 often comes at a better price.

Once I've gotten it broken in and well practiced then I'll start to worry about what defensive ammo it might like the best. I keep SIG V-Crown 115gn JHP ammo in my SIG 320 Compact "house gun". I have several brands in my ammo cabinet ... Lawman, Blazer, Federal, Colt National Match, Nosler .... my well shot SIG 320 X5 (non-Legion) runs flawlessly with any of it. YMMV

 

Welcome from Tennessee and God bless you!

 

I usually take a variety of ammunition to the range and shoot a gun off sandbags to see what it’s most accurate with. That said, most of the Sigs I’ve tried are most accurate with 124 grain jhps

 

124gr standard velocity.
IMO, that's the sweet spot for 9mm ammo.

Use the well-regarded practice ammo such as Blazer Brass, Fiocchi, etc.
Federal HST or Speer Gold Dot for self defense ammo.

I don't dabble in steel case or aluminum case ammo.