115 or 124 grain during break-in period?

[sacosta66]

Get yourself a couple boxes of 115 grain FMJ ammo and head to the range. After 100 rounds you will be broken in, after the 1st shot your pistol will be good to go.
Get out there and have some fun with it. Its a great pistol!

 

[patrickd]

The only thing that happens during break in of a pistol is those parts that the builder didn't take the time to stone and polish so they mate together properly, wear in by rubbing together. If manufacturers spent more time fitting parts vs slapping two parts together there would not be any break in at all. Unfortunately old world craftsmanship is gone forever in the mass production of firearms and most everything else these days.

 

[Arc Angel]

The only thing that happens during break in of a pistol is those parts that the builder didn't take the time to stone and polish so they mate together properly, wear in by rubbing together. If manufacturers spent more time fitting parts vs slapping two parts together there would not be any break in at all. Unfortunately old world craftsmanship is gone forever in the mass production of firearms and most everything else these days.

Depends!

It isn't common knowledge; but brand new polymer firearm frames need to, 'relax' and take something of a, 'set' before they can be trusted to perform reliably. The best way to do this is to repeatedly fire the gun. With a brand new polymer frame pistol I'd, personally, recommend breaking it in with a minimum of 500 rounds. (On pistols I've had some sort of a problem with I've gone as high as 1,000 fired rounds before carrying.)

April, 2016 issue of the NRA's premier magazine, ‘Shooting Illustrated’. On page #10 there's an article titled, ‘Plastic Fantastic’; and I quote:

"In terms of a pistol frame, the tip of the barrel is where specific heat is applied, although the barrel is not touching the frame."

"This heat (referring to barrel heat and new polymer that's still stiff from the molding process)(Ed.) is predictable and therefore the injection mold is designed to manufacture the frame with THE ULTIMATE RELAXATION (emphasis added)(Ed.) of the material in mind .... .”

“(After receiving a proper break-in)(Ed.) it does not impact performance or accuracy.''

“IT TAKES 500 TO 1,000 ROUNDS FOR THE POLYMERS TO RELAX.”

~ Dave Borges, CEO, Polymer80 Corp.

 

[Skeptic 9c]

I've run new guns, usually without failures with 115 gr Name brand range ball ammo. Winchester White Box and the equivalent. But a young gentleman of youth and enthusiasm who plays King of the Swampy Desert in competition has gone all 124 gr because a batch of 115 gr didn't make minor. Fortunately it wasn't a record match, just a local club, but he is all 124 since.
Geoff
Who doesn't blame him, imagine getting DQ'd for ammo before the match!

 

[palmettostate1]

Put 9mm ammo in the gun out of box of factory ammo. Shoot it. Have fun.

It matters not, what grain you choose.

Why only "factory ammo"?

 

[DataPimp]

Why only "factory ammo"?

Because there are idiots that don't know how to reload properly and their rounds can cause malfunctions.

If someone can actually reload correctly and the rounds run fine then great. I would never run reloads in a SD gun, that's just not me.

 

[garyez]

No Difference

In last 12 months have bought 2 brand new 9mm semi-autos, a M&P 9L Pro and a G17, and used both 115 and 124 grain ammo in the first hundred rounds through both with no difference in function. My LGS sold me some 115 grain Aguila with one of these and said something about it cycling the slide faster but I've not noticed any difference.

Think that S&W customer service probably says for all their new firearms that a break-in period of 300-400 rounds is recommended but functionally all semi-autos should be 100% out of the box except for a few minor issues like sometimes not holding open on the last round or slightly heavier trigger weight than advertised. Such minor issues usually improve as the surfaces of new parts wear in on each other.

 

[hoc9sw]

Why only "factory ammo"?

Not just "factory".

For me it is a matter of being prone to break anything I touch (so guns tend to go back to the factory for repairs of all sorts). The owner's manuals do tend to advise you use factory ammo / saami-certified, and may advise against aluminum / steel case, no reman or reload, no +P+. Some, like HK, will tell you the warranty is effectively voided by certain ammo. It is up to you. If the gun has a failure, and you have to send it back, you will probably be asked what ammo was in use, and the answer may determine if they handle it as warranty, or expect you to pay.

I have settled on a few types of ammo that meet the specs of all the manufacturers, and actually work in the guns I have, so that I don't have to worry about being caught with a gun / ammo combo that doesn't work.

Good example - my EMP 9 will not run ZQI Nato rounds due to the very hard primers. Every other gun down to the Shield run it without issue. The EMP 9 may get sold, depends on how long those cases of ZQI last. It has been back to SA twice, they say it is in spec, and they don't like ZQI. Oh well ....

 

[palmettostate1]

Not just "factory".

For me it is a matter of being prone to break anything I touch (so guns tend to go back to the factory for repairs of all sorts). The owner's manuals do tend to advise you use factory ammo / saami-certified, and may advise against aluminum / steel case, no reman or reload, no +P+. Some, like HK, will tell you the warranty is effectively voided by certain ammo. It is up to you. If the gun has a failure, and you have to send it back, you will probably be asked what ammo was in use, and the answer may determine if they handle it as warranty, or expect you to pay.

I have settled on a few types of ammo that meet the specs of all the manufacturers, and actually work in the guns I have, so that I don't have to worry about being caught with a gun / ammo combo that doesn't work.

Good example - my EMP 9 will not run ZQI Nato rounds due to the very hard primers. Every other gun down to the Shield run it without issue. The EMP 9 may get sold, depends on how long those cases of ZQI last. It has been back to SA twice, they say it is in spec, and they don't like ZQI. Oh well ....

I am up to loading and shooting about 260,000 rounds since 1997. I estimate I have only purchased 5,000 factory loads in the same time frame.

With the money I have saved I could by 20 of my $500 Glocks or M&P's and maybe a handful of my 1911's and AR's.

Every pistol I have ever owned including Beretta, Glock, M&P, Walther, H&K, Sig, Kimber, Springfield and Colt have fired my reloads without fail. I trust my loads and will continue to do so.

I remember a few years ago when ammo supply dried up, the only people still shooting at the matches were those of us who reload.....ahhh, good times.

If supply of your favorite/approved ammo dries up, your guns will be paperweights.

 

[palmettostate1]

Because there are idiots that don't know how to reload properly and their rounds can cause malfunctions.

If someone can actually reload correctly and the rounds run fine then great. I would never run reloads in a SD gun, that's just not me.

Agreed, I reload for competition and practice but carry factory SD rounds.

 

[Mark IV]

There have been a lot of comments stating that modern pistols don't need a break-in peroid, and while this has largely been my experience as well, the fact remains that a lot of pistols will experience a couple glitches early on, and then "break in", and run flawlessly ever after.
IIRC, Ruger advises a thousand dry-fires with their revolvers to help them "break in", and the Rock Island's 1911 manuals tell the owner to fire a full 500 rounds, before even calling them about any issues.
But again, when I immediately run a couple hundred rounds through a new toy, I'm not so much trying to break it in, as I am just confirming 100% reliability, though I'll still use the general term "break in".