M&P9 2.0 CORE Slide Shifts Left

[Grampy99]

Recently bought a new 4.25” MP9 Pro Series CORE and installed Holosun red dot. Learning to shoot it, but while dry firing it I can see that the slides moves a specific, consistent distance (about 2” at 10 yds) to the left when I fire. Checked red dot for tightness. Confirmed if I place weak hand index finger ON the slide and push to right, red dot stays on target when firing. (Can’t do that for live fire....)

Do I have a problem? My other semis are much tighter.
Just joined forum today.

 

[mckenney99]

I'm not sure I'm understanding your problem correctly. Are you seeing your red dot shifting to the left when you pull the trigger? If so, that is not unusual for persons just getting use to the trigger on any new pistol/revolver. You will need to work on the placement of your trigger finger on the trigger and stroke straight back on the trigger. You may have your trigger finger too far into the trigger and are pushing the pistol to the left as you compress the trigger.

 

[Grampy99]

Thank you for the response.

I understand the tendency to pull left when grabbing too much trigger and have tried to adjust my trigger press to minimize it while practicing. Will continue to work mytechnique.

The dry fire exercise shows the red dot moves to the left EVERY time I dry fire unless I place weak hand index finger against the slide. Then there is no shift

Groups shot by me and my buddies at 10 yds show VERY mild tendency to left but that could be red dot calibration. Only have about 300 rounds through it so far and want to get ME trained before I start changing things.

Just odd to see the dot jump horizontally EVERY TIME.

 

[Gun Geezer]

Grampy, you are not going crazy.

I have the same issue with a new 3.6" compact that I had milled for an RMR. When dry firing, the dot jumps to the left when the trigger breaks. I thought that seemed weird because I have another identical 3.6" milled by the same company (AETi) with an identical RMR (RM06)and it doesn't move when dry firing. Both guns have apex forward set triggers installed.

I swapped every combination of recoil springs and slides between the two frames and it appears to me that the slide of the new gun is the culprit.

If you hold the gun horizontally and look down at the slide, , you'll see the slide jump left in relation to the frame when pulling the trigger. It's weird however, I haven't noticed a shift while shooting.

Hope this helps.

 

[Ethang]

I have the exact same problem on the full size Core I bought early last year. A consistent "twitch" of the dot to the left. At first I thought it might just be I had developed a glitch in my trigger press that was magnified by using the dot sight. However, switching to left hand the twitch is exactly the same, to the left. It would be to the right if it was a defect in the trigger press.

How are your results during live fire? I have not shot mine that much, but my POI is not effected by this twitch.

 

[WR Moore]

Just out of curiousity, have any of you tried dry fire with dummy rounds in the chamber to see if the "problem" still exists?

 

[Ethang]

Just out of curiousity, have any of you tried dry fire with dummy rounds in the chamber to see if the "problem" still exists?

Two things. One this twitch is a consistent, repeating, amount and always to the left. Dry firing with the left hand would reverse any trigger press issue caused by a flinch, it would not be the exact same movement to the left. If it was shooter induced it would not be a constituent track of the dot, it would vary with the amount of flinch.

I am very familiar with trigger press issues, at least in my weapon this is not one.

 

[Gun Geezer]

I rechecked my 2018 3.6 and my 2021 3.6 and found both have a shift to the left. The 2018 has a much less pronounced shift but it also has 6,300 rounds through it. The 2021 only has 150 rounds through it at this point. I wonder if more rounds through it may help.
I decided to check my 2016 shield and it also has a slight shift to the left that I'd never noticed before. The shield has XS Big dot sights so it was probably less noticeable than the red dot guns. The shield has about 4,000 rounds down the pipe.

Maybe it has something to do with the way the trigger bar engages the striker block on m&p's. It looks like it may engage the striker block on the edge of the block rather than dead center.

 

[WR Moore]

Two things. One this twitch is a consistent, repeating, amount and always to the left. Dry firing with the left hand would reverse any trigger press issue caused by a flinch, it would not be the exact same movement to the left. If it was shooter induced it would not be a constituent track of the dot, it would vary with the amount of flinch.

I am very familiar with trigger press issues, at least in my weapon this is not one.

I'm familiar with trigger press issues also, and I wasn't thinking of that. The suggestion was to see if the issue might be a little play in the slide/barrel/frame fit that might not be present if there was a round in the chamber.

 

[Ethang]

I'm familiar with trigger press issues also, and I wasn't thinking of that. The suggestion was to see if the issue might be a little play in the slide/barrel/frame fit that might not be present if there was a round in the chamber.

My apologies. From your post I inferred you were talking about a poor trigger press.

Interesting thought you touched on though. I will try with a dummy round and see if that effects it. Since the POI is not changed I have never really pursued the matter. Just was interesting to find out others have the same thing occurring.

 

[WR Moore]

A loaded magazine that puts pressure on the slide might also have some slight affect.

 

[Grampy99]

I just joined the forum yesterday and am really impressed for all the help and wisdom. Many thanks to all.
Experimented with snap caps and with/without mag. Learned the movement was almost neutralized with snap caps with or without mag.

5 of us fired this weapon and there is no pattern of drift to the left with live ammo.

Glad to see others noticed these tendencies. Was thinking of sending it to S&W until I heard from all of you. Again, many thanks.