My M&P9 and a few terminology questions

[Tornado_Racing]

I have had my M&P9 for about 6 months now. I traded in my Taurus PT840 for the M&P after a fellow shooter let me send a few downrange with his M&P. The fit/feel of the M&P and how it felt like it was made to fit my hand led to the swap. I'm a DYI kinda guy so I installed the full DCEAK, removed the internal lock & installed a RAM, stippled my frame, press-fit & glued a spacer to move the trigger closer to the back of the trigger guard/closer to the mag-well, and cut and fitted a custom kydex grip extension over the takedown lever for the left thumb (I have short fingers). My Taurus had 5K+ run through it as it was a range gun but I was really fond of the trigger. When shooting my Taurus the trigger position was very close to the frame (with the hammer back). When the hammer was up or on safe the trigger would move to the front of the gun. I really grew fond of the little squeeze I had to use to fire the pistol. The trigger on my M&P required alot of pull (take-up?) until the trigger set. This was very hard for me to over come hence the spacer to move the trigger to the rear like my Taurus. The mods I have done dramatically improved my grip and accuracy compared to a stock M&P.

Here are my questions:

1. What is the difference between a single action (M&P?) and a double action pistol (PT840?)?
2. What is trigger take up?
3. What is reset gap?
4. What is pre-travel?
5. What is over travel?

Any and all info would be greatly appreciated. If these are "noob" questions I appoligize in advance. I just want to get a better understanding of the differences between the 2 triggers.

Thanks,
Tony
Tornado_Racing

[John_Wayne777]

Here are my questions:

1. What is the difference between a single action (M&P?) and a double action pistol (PT840?)?


Double action refers to the function of the trigger. On a double action pistol, the trigger cocks and releases the hammer/striker to fire a shot. On a single action, it simply releases the hammer/striker.



2. What is trigger take up?


Keep in mind that terms in the gun world often mean different things to different people based on where they heard them...

Takeup traditionally refers to movement of the trigger prior to the point where it is actually manipulating the firing mechanism. On the M&P if you begin to press the trigger to the rear with minimum pressure you'll be able to move the trigger up to a point. To move beyond that point you need to apply more pressure. That point is called the reset point, the position in the trigger's arc of movement where it is engaging the sear and beginning to move the firing pin block out of the way.

Takeup is also referred to as "slack" in the trigger.



3. What is reset gap?


I have no idea. I've never heard that term before.



4. What is pre-travel?


In my experience, pre-travel is a synonym for takeup.



5. What is over travel?


Overtravel is trigger movement to the rear after the point where it releases the sear/striker to make the weapon actually fire.

You've done some fairly extensive modification to the trigger on your M&P already....keep in mind that reducing the arc of the trigger's movement also reduces the tactile feedback of a trigger pull. In other words, it reduces the opportunity for you to realize the trigger is being pulled. This can be a bad thing under stress.

[Tornado_Racing]

Thank you for the reply. Seems as if the words kinda mean the same thing.

With the mods I have done/installed the DCEAK has reduced over-travel/reset point and the trigger spacer has reduced pre-travel/take-up?

I still have roughly 3/16" take up along with the heavier Apex trigger spring.

[highxj]

Something you'd better check is to make sure your takeup mod doesn't leave the trigger bar so far back that the striker block is is being activated when the trigger is at rest. You *should* be okay with the Apex sear......but I'd check anyway.

[Tornado_Racing]

This was researched prior to the spacer being installed using this thread M&P Striker Block Internal Safety (http://mp-pistol.com/boards/index.php?showtopic=19143) and a flashlight through the back of the slide to check trigger bar/striker block engagement during trigger movement.

[highxj]

Good enough, sounds like you understand the mechanism......not everybody does. Too many people start tearing into things and 'modding' them without fully understanding how everything functions.