Recently purchased a 4.25" M&P 2.0 TFX, after a few range visits now I notice my shots would inconsistently pull left on the target at 15-20 yards. After cleaning the pistol I looked at the back of the slide and after racking it it stays back a marginal amount then once I squeeze the trigger *Snap Cap in chamber* the slide moves forward 0.015-0.025" and the rear shifts leftward. I would estimate it's because the striker spring is new and strong but has anyone else experienced this and does it go away? the pistol is surprisingly accurate when the slide does return to the full forward position.

You didn't say how the slide went forward before you dry fired. In normal functioning, the slide slams forward with considerable force to reach true battery position. It certainly isn't 1/10 inch out of battery. Thus, the slide isn't gonna boogie about-at least anywhere near as much as you suggest.

Having worked with a slew of people during transition training to the M&P series, the most likely explanation of your errant shots is your incomplete mastery of the trigger stroke. Continue your dryfire with your attention on your sights and the target, not the slide. Also work on your grip, it should be firm with tension from the support hand.

To paraphrase a well known trainer, "It's not the arrow nor the bow, but the Indian".

My apologies for not stating that, I slingshot the slide forward with a snap cap in a magazine. So it would theoretically load as it would while live firing. And I had to look back over my calipers 0.1" is an overestimate as you've pointed out I updated the original post.

As for my training this is my third M&P pistol, I have an early gen I retired police issue pistol and a viking tactical model. Both of which I have owned for several years, I'm familiar with the trigger itself and thought I was throwing the shots on occasion until I inspected the pistol. My focus while shooting is primarily on the front sight, I only noticed the slide shifting slightly after I cleaned it and put a snap cap to test for proper function.

OK, you're familiar with the trigger. Sorry about that, chief. That said, I still expect the major issue, since it's windage, is still you. Everyone has had occasional lapses like that.

I've never dry fired with snap caps, but virtually every self loading pistol I've ever dry fired while watching the slide has exhibited some movement-a hard fitted 1911 excepted. So long as the barrel locks up consistently with the slide, slight movement of that slide doesn't really have all that much effect or shot placement.

Since the piece is still new to you, I'd suggest more practice and see if the issue continues. Might need a few things worn in also.

You're fine I'm not sure what it is exactly but it's only a small deviation of 0-1.5" to the left, today was 17 yards.

I have only put 250 rounds down range. Maybe like you said it still needs breaking in I'll send several more boxes down range and hopefully everything will settle into place.

I will say though the trigger is the same hinged unit from previous generations which isn't fantastic but the rest of the action on this pistol are nice from the factory.

There is also a difference in hand loading a bullet into the chamber as opposed loading from the magazine as fas as the slide closing properly. Some weapons will damage the extractor when hand loading the bullet without loading from the mags. Just a thought and dosent apply to the shooting low and left.

I need to slightly amend that comment about slight movement of the slide under hammer/striker function: you generally won't see that on handguns with enough use to have the various parts properly mated. You can see that movement on NIB/lightly used handguns.

Added material: had a chance to check a well used M&P9. With the slide hand closed, dry firing on an empty chamber did show a slight sideways movement of the slide at the rear. However, let's think about this. You have the recoil spring applying 16 lbs of force at the lower front of the slide. The striker spring applies 5 lbs of pressure opposing this. When the striker/striker spring tension is released, the rear of the slide may move slightly due to the lack of opposing spring tension. I would expect that this is repeatable and consistent and would have no significant effect on shot placement.

The trigger digit is responsible for far more displacement of shots than minor parts play.

Low left is almost always a sign of losing patience with the trigger stroke and finishing up with a hearty yank.

It's a new pistol for you. Do some dry fire practice and see if it doesn't improve. Being that you have other well broken in pistols this one may just need some over time smoothing out.

Inconsistent lock up will produce inaccuracy. Very, very few new guns have inconsistent lock up.

Could your snap cap have a rim that is too thick?

I would try letting the slide slam forward on an empty chamber, no mag inserted.
Is the slide all the way forward?
Is the barrel hood locked up tightly in the slide? Front to back, side to side?
Is the muzzle firmly held in the front of the slide?
Can you get more than just a tiny bit of slop when moving the slide side-to-side on the frame rails?

Also try easing the slide forward to close on an empty chamber. Do you feel a significant hitch at lock up? This is normal on a new gun. With repeated cycles it will wear to be smoother. However, if it is significant and actually keeps the gun from going into battery, then breaking the sharp edge on the barrel hood where it locks into the slide will remove that resistance from going into battery.

Now, as to inaccuracy of ~1.5” at 17+ yards, you’re one hell of a shot. Until you shoot seated from a good rest, supporting your hands and arms rather than the flexible frame of the gun, with perfect grip, sight alignment and straight trigger press, you won’t really know what the gun is capable of without so much human interference. Slow fire. 10 rounds. Perfect shot each time.

You don't need a snap cap to dry fire a striker fired pistol, so try it without one. I've dry fired 1000+ time with mine to get used to the trigger. It's a practice technique that is widely recommended by top instructors.

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I guess an update I have is I've tried a weaker firing pin spring and it has taken care of the slide locking up at some small angle. Thank you guys for the input but it looks like the factory spring just needs more breaking in, until then I can't expect perfectly consistent shots.

My guess is it will not do it with a magazine inserted

In your original post you indicated that you were shooting left on occasion. You also stated that when the striker engaged the slide the REAR of the slide shifted to the LEFT.

Picture looking at your pistol from above. Now picture rotating your pistol 90 degrees in the CLOCKWISE direction, a rotation direction that has the rear of the slide moving to the LEFT. So, what direction is your pistol pointed after that 90 degree rotation. Yeah, it is pointed HARD RIGHT. Kind of shoots down you theory that the rear of the slide kicking left is the reason you are shooting left.

Typically there are just two mechanical factors that cause a handgun to shoot left. One is loose sights and that can also cause scattergun targets. The second is a badly out of adjustment sight, something not very typical with modern semi auto pistols.

All of the other causes for shooting left fall in the hands that are holding the pistol.

Any update to this issue? I just noticed it myself. I have a very lightly used 2.0 with an Apex trigger and compared it to a lightly used 2.0 CORE with Apex barrel and trigger. Both exhibited slight forward movement of the slide upon trigger break. I would even push the slide forward to make sure it's in battery but it still does it. I'm disappointed in this likely design flaw. Apex is aware of it as well. Slight movement of the slide and barrel translates into measurable deviation on target.