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Author Topic: M&P Sear Question  (Read 3517 times)

Coronach

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M&P Sear Question
« on: August 12, 2013, 06:27:23 am »
There are currently three common options for a trigger job on the M&P:

1. DIY on the OEM sear.
2. Apex drop in "Hard Sear"
3. Apex gunsmith fit hard sear.

The Apex sears are tool steel and the OEM sear is, IIRC, MIM. Is there a real benefit to using an Apex sear over the OEM sear? Bear in mind that the end product will be dimensionally end up being pretty much the same (the Apex drop-in approximates the Burwell trigger job's sear, and the Apex gunsmith sear or the OEM sear would end up being profiled by me to mimic this), so the real question is probably only a material and cost issue.

I get that tool steel is better than MIM steel. But is it $40 better? Have there been instances of MIM sears failing?

Mike

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    strangelittleman

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    Re: M&P Sear Question
    « Reply #1 on: August 12, 2013, 07:50:44 pm »
        I do not know of any M&P sears failing. I also do not know of any of S&W's revolvers' MIM hammers or triggers failing. S&W has got the "casting" of MIM parts down very well. So long as MIM is done correctly by a quality outfit, there is (to me) minimal to no difference.
        I just spent the last week at a very demanding school where we shot the hell out of our issued M&P40s and those things got better and better in the trigger dept. In the last 6 months, I've put probably 2,500rds + through my service pistol and don't need anything done to it. The trigger is better now than it ever has been.
        To me I don't think the cost would produce a tangible difference that dry firing and live firing wouldn't in time, give anyway.
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    Coronach

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    Re: M&P Sear Question
    « Reply #2 on: August 13, 2013, 01:13:36 am »
    That's kinda my thought as well. S&W uses a lot of MIM parts, but they seem to use a good MIM process and they seem to use the MIM parts in places where they work well. Tool steel is amazingly durable, but if MIM gets the job done for a fraction of the price, it hardly seems worth upgrading. For a frame of reference, either one of the Apex tool steel sears runs about $50, delivered. A complete sear housing block from S&W runs about $30, delivered. So, for $20 less you get a complete SHB, a drop-in assembly. If nothing else, that gives you a nice supply of spare FSBs (fiddlin' small bits).

    As far as the M&P trigger goes, out of the box the newer ones are a little gritty, mushy and busy. As SLM says, they clean up nicely in use. There are a couple of things that I think (ok, me and a lot of other people) can be done to make them better that they won't do on their own (in order of least important to most):

    - Address the busyness/mushiness of the take-up. When you pull the M&P trigger back to the "wall" (where you engage the sear), it can be a little spongy and ... busy. There is something indistinct going on, and it bothers some people. What is happening is the trigger bar is pushing the striker block (silver circular thingy on the underside of the slide) up and out of the way of the striker. If you 1. polish the part of the trigger bar that engages the striker block and 2. polish the engagement surface of the striker block, turning it from flat-topped to a smoothly rounded dome, this greatly reduces the sensation of "something going on" and smoothes everything out without lightening weight.

    - make the release a little more crisp. This can be achieved by polishing the engagement surfaces of the sear and striker (just polish, no changing angles)

    - heavier reset. I've tried putting a sliiiiight bend in the trigger bar (slow your roll, I said "slight"). It helps. Reprofiling the sear cam lobe (see below) helps too. I also have an Apex RAM that I want to try but have not yet installed. This is the one area where the Glock absolutely smokes the M&P trigger out of the box, and even tweaked it can still be easy to short stroke it.

    - Reduce overtravel. This and the reset are the big two. If you reprofile the sear cam lobe (flatten it out) so the sear is engaged later, you will add to the take-up distance and remove a corresponding amount from overtravel. This is beneficial to accurate, fast shooting, but think small- if you remove too much, you'll affect reliability. Reprofiling the sear cam lobe can also lighten weight a little and you can polish everything up while you're doing it.

    Add these all together (this is essentially the Burwell trigger job), and you have a very very VERY good service trigger; not much lighter than stock, but wonderfully clean and crisp.

    Mike
    « Last Edit: August 13, 2013, 08:15:30 am by Coronach »
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    Coronach

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    Re: M&P Sear Question
    « Reply #3 on: August 13, 2013, 01:18:18 am »
    FYI, this is the difference between the two Apex sears. The gunsmith-fit sear is essentially a tool-steel version of the OEM sear. The Apex "hard sear" is a tool-steel version of a sear with a reprofiled sear cam lobe and, presumably, it is polished up pretty smooth (not sure about that).

    Mike
    OhioNot stressed, but I am a carrier.

    seanp

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    Re: M&P Sear Question
    « Reply #4 on: August 13, 2013, 08:47:51 am »
    If you look at the sear as well, there are none of the areas of concern that I would have with a powdered metal part such as corners that have a sharp internal radius, and so forth.

    The key difference would be wear resistance.  Depending on the hardness and formulation of the MIM part, it will have different wear characteristics than a traditionally made part, but without knowing the composition and hardness of the OEM part and the composition and hardness of the Apex, it would be difficult to knowledgeably speculate.

    Given that the sear does not seem to be a high failure part, I am not sure that it matters which you go with.  That being said, I am getting a spare set of parts (OEM) before I attempt my own Burwell job.
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    Coronach

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    Re: M&P Sear Question
    « Reply #5 on: August 13, 2013, 09:23:20 am »
    That's exactly what I did.

    I may eventually spring for a Hard Sear, but it will only be after I'm pretty solid on doing the Burwell job. It's not hard, but I'd rather practice on a few more $20 parts that come with components that are still useful even if I screw up the sear than on a $40 sear that becomes useless if I take off a touch too much metal. Plus, having a spare SHB on hand is nice of you completely screw up the job. Take ruined sear out of SHB, sit SHB aside to serve was a warning to others, put new SHB in the gun and ponder whether or not you want to do that again. ;)

    Mike
    « Last Edit: August 13, 2013, 09:56:24 am by Coronach »
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    strangelittleman

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    Re: M&P Sear Question
    « Reply #6 on: August 13, 2013, 08:00:22 pm »
    Wow, I've learned a lot from this thread!
    Semper Gumby.....Always Flexible.
    Vision without action is a daydream, Action without vision is a nightmare.
    Zol zayn azoy.

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