I purchased a new P365. First time to the range I fired 150 rounds of Remington and PMC 115gr FMJ. Utilized two magazine and and experience one to two failure of the slide to go fully foreword with every magazine fired. Anyone else have a similar problem.

Failure to return to battery can arise from not gripping the gun firmly when you fire it. AKA limp wristing the firearm. Sometimes with small guns its easy to do this without really noticing. So, how's your grip?

I don't have a P365, but I had one of the infamous Glock 30SFs with a failure to return to battery issue. I know how frustrating it can be when a new gun doesn't perform as you had hoped.

You COULD be limp wristing or riding the slide with your thumb slowing velocity.

That said my guess is weak ammo, new gun. 115 grain stuff may not have the oomf to overcome a tightly sprung mini gun at first. Clean, lube well, leave slide locked back for a few days or work the slide by hand / dryfire a bunch too. and run a box or three of hotter and or heavier ammo. 124/147 grain and or defensive or +P stuff. Winchester 124 grain NATO spec works well for this usually.

Full disclosure, I don’t have a 365 but I do have a wide range of experience with a lot of different platforms and what you are describing really screams break in issue. My guess is it won’t take long before you can run 115 grain powderpuff stuff reliably.

My P365 did that a total of two times the first time I took it out. After about a hundred rounds I had no further problems...I think it just needed to wear in a bit.

I had a similar problem with a 365XL. It failed to return to battery several times with each mag, and with 124 gr ammo as well as 115s. When it didnt work itself out after about three or four boxes of ammo, I called Sig and sent it in. It was back in my hands exactly seven days later with a new recoil spring. Hasn't skipped a beat since. Really quick turnaround and spot-on service from Sig.

quote:

Originally posted by 92fstech:
My P365 did that a total of two times the first time I took it out. After about a hundred rounds I had no further problems...I think it just needed to wear in a bit.

Same here. First hundred rds. it failed to fully return to battery a few times but then stopped doing it. Shoot it a little more.

did you clean and lube it first???...I recall when I bought mine I was told to clean and lube it before shooting several times by the place I bought one at...

mine has run 100% with Speer Lawman 124Gr and Speer Gold Dot 124GR as well as SIG Elite V-Crown 124GR (the regular version)...

Good luck with yours

Bill

Gut it out and shoot the thing. Took about 150 rounds of "break-in" for one of my 365s before its return-to-battery failures worked itself out. My second 365 has been flawless (knock wood). 3700+ total rounds combined with most through the problem one (roughly 60/40 ratio), one RSA replacement for the problem 365 done early. I wanted to see if a new RSA would bring back the issue; fortunately it did not.

I usually am NOT a believer in the concept of a gun needing a break-in period, like seasoning some damn skillet or some such. But I like the form factor of the 365 so I worked with it. And have probably shot both more than I planned to in my first year of ownership as a result. Problem guns will do that to me.

-MG

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I usually am NOT a believer in the concept of a gun needing a break-in period,

We have to remember that 9mm is not all that powerful and has a WIDE range of weights and powder charges. When you add in the fact that we want the guns to reliably fire hot defensive ammo and be durable and complicate it with I want the SMALLEST package possible you are going to have to deal with some break in from time to time with crappy powderpuff 9mm.

.40 and .45 and .357SIG etc. are more forgiving cartridges because even there target stuff is still reasonably powerful ammo.

You should never have to shoot 500 or a 1000 rounds to break in. Having to shoot a box or three of hot/heavy/better stuff is no big deal IMO.

I always break my 9mm firearms in with 124 grain NATO or similar.

Another suggestion I've followed, after the clean and lube, is work the slide 100 time before first shooting the firearm.

Seems to help.

quote:

Originally posted by cslinger:

quote:

I usually am NOT a believer in the concept of a gun needing a break-in period,

We have to remember that 9mm is not all that powerful and has a WIDE range of weights and powder charges. When you add in the fact that we want the guns to reliably fire hot defensive ammo and be durable and complicate it with I want the SMALLEST package possible you are going to have to deal with some break in from time to time with crappy powderpuff 9mm.

.40 and .45 and .357SIG etc. are more forgiving cartridges because even there target stuff is still reasonably powerful ammo.

You should never have to shoot 500 or a 1000 rounds to break in. Having to shoot a box or three of hot/heavy/better stuff is no big deal IMO.

I always break my 9mm firearms in with 124 grain NATO or similar.

I second the 124 NATO or similar comment...I’ve made it standard practice.

I ran a few hundred 9mm NATO through mine at first and never missed a lick.
Like others that's all I use on a new gun.
The Winchester M1152 is a hot lil 115gn pill that has plenty of oomph.
All the range has is 115gn and it's been reliable with that, usually Magtec.

I just picked up a lightly used one with a born on date of July 2019.
I ran 150 rounds of NATO spec Fiocchi through it today with no issues. Accurate but snappy with that ammo.
I will run about 500 rounds or so more through it before I carry it.
So far, so good.