The P365 isn't all sunshine and rainbows as received. At least mine wasn't.
The most serous issue was that the stripper rail was so rough that it put deep scratches into the shell cases and it made it very difficult to retract the slide over a magazine loaded to capacity. Several other people reported the same issue. I'm not sure if this was a small batch of P365s that weren't finished properly or if they are all like this.
Most people will not even realize this problem even exists, as they will chamber a round and then insert the magazine to carry +1, and they have no need to retract the slide. UNTIL they need to pull the trigger in a self defense situation, the gun goes "click" but no boom because the cartridge is a dud, and suddenly they quickly need to retract the slide over the magazine that is loaded to capacity. To compound matters, their hands may be sweaty or otherwise slippery and they may find it difficult to impossible to retract the slide! This will be especially true for a man with arthritic hands or woman with weaker hands.
Eventually the brass shell cases will polish the stainless steel stripper rail. But how many thousands of rounds will that take? The fix is simple. Remove the striker assembly and the striker safety because they are in the way. Mask off the hole for the extractor pivot pin to avoid contamination. Then hand wet sand the stripper rail until smooth. It took less than 10 minutes the first time I did this. Then I cleaned up the slide and especially inside the striker channel, as this is supposed to remain bone dry without lubrication. Reinstall the striker safety and striker assembly and the job is done. If you are competent enough to remove and replace the striker assembly you can easily perform this polishing yourself.
The result is that it now it only requires slightly more force to retract the slide over a magazine loaded to capacity than it does to retract the slide over an empty magazine.
The second issue is that fresh out of the box the P365 can have return to battery malfunctions due to excess friction caused by parts not finished as smoothly as they should have been, and secondly, during the break-in of the recoil spring assembly it can crud up a bit inside causing excess friction. I noted that the left adjacent wall to the breechface was rough enough that it ground brass off of the shell cases, the extractor claw was sharp enough that it shaved brass particles off the the shell cases, and the underside of the extractor claw was rough. The breechface itself could use a finer finish.
I hand wet sanded the breechface, the left adjacent wall to the breechface, the underside of the extractor claw, and I used a fine diamond whetstone to dull the edge of the extractor claw just enough so that it would NOT shave brass from the shellcases. This does require considerably more mechanical aptitude than the average person has.
The RSA should be solvent cleaned after a break-in of 200 or so rounds fired, allowed to dry, and then relubricated. This anyone can and should do.
Also, you need to keep the breechface clean! Gunpowder residue on the breechface increases the friction against the rear of the shellcase sliding across the breechface to achieve the correct angle to enter the firing chamber, and this friction makes it more difficult for the slide to return to battery.
After I performed this polishing work, there is NO way that you can ease the slide closed slowly enough that it will NOT return to battery. I still release the slide quickly and let the slide slam closed into battery. But it's nice knowing that I have an extra margin of reliability.
Polishing the beveled leading edged of the extractor will also make it easier to manually chamber a cartridge.
As received the trigger will feel gritty. You can remove most of this grittiness by dry firing. But you can also go the extra mile and polish the trigger linkage contact points and make the trigger even smoother. This will NOT change the action of the trigger or change the required trigger pull force. But it will make it so smooth that you can feel the point when the trigger spring stops rotating and starts bending, when the sear spring begins to engage, when the FCU slides backward about 0.010", and finally you can feel the break. Many people do not think that the P365 break is sharp enough, but this is a $500 self defense pistol, not a competition race gun. FYI, most people don't notice the FCU sliding backward until you point it out to them. You can do some shimming to eliminate the FCU movement if it bothers you.
By now some people will be crying out that the sky is falling and that I'm causing the end of the world with these "modifications". But in reality, eventually these parts will become worn smoother from use on their own. But I don't want to have to fire 10,000+ rounds for this to happen. I just sped up the break-in process so that my pistol is working perfectly today.
When the magazine is near empty, the P365 feels floppy in your hand because it will be top heavy. I made a 1.75 oz tungsten weight and glued it inside the handgrip and that eliminated the floppiness. I think that is also reduced the muzzle flip slightly. I'm not the only one that is concerned with this balance issue as Wilson Combat makes a replacement handgrip module that allows you to insert a 1.5 oz tungsten weight. I'm sure that this is a typical issue with polymer frame pistols. Some people will complain that the extra 1.75 oz of weight is intolerable. I think that it's more important for the feel of the pistol to be more consistent from loaded to empty. It also makes it easier to insert a magazine, as you physically cannot insert the magazine at the wrong angle.
I also prefer the taller XL handgrip module, so I bought one and installed it. I added a 2.0 oz tungsten weight inside the handgrip.
If you are using the taller XL style grip module with the beavertail, I recommend that you use some fine sandpaper and slightly radius the corners of the beavertail so that the web between your thumb and forefinger doesn't get hung up on the beavertail during a draw.
I didn't like the way that the sharp corners at the bottom of the grip module and magazine floorplate felt in my hand, so I sanded a gentle radius into them. This may or may not be of benefit to you depending upon the size of your hands. I also sanded out the mold seam on the trigger guard. This may seem trivial, but I'd rather eliminate the possibility of noticing a distracting irritation while shooting.
The stock magazine release button is nearly flush by design, and I cannot operate it without rotating the pistol in my hand. But by extending the magazine release button to the normal amount of protrusion, I no longer need to rotate the pistol in my hand while swapping magazines. This is a personal preference issue and an extended magazine button may or may not be of use to you depending upon the size of your hands.
For me and my XL sized hands, the trigger is not far enough forward. I would like the trigger to be moved 7/8" further forward. But this will be an issue I have with most pistols as they are made "one size fits all".
Would I buy a P365 again with all of it's known issues? In a heartbeat. When my budget can afford it, I will be buying a P365XL and my P365 will be relegated for pocket carry.