I've got an old 1.0 5" 9MM PC I really like.  I keep spending money on it trying to get it to shoot better though.

I bought a used 2.0 sear housing and trigger/trigger bar to see if it would work in the 1.0 frame.

The 1.0 already had an Apex trigger in it.  I decided to see if the old 1.0 Apex trigger would work on the 2.0 trigger bar with the 2.0 sear housing.

Won't go through all the silly alignment (pins and parts) issues but I finally got it together.  Only to find the 1.0 Apex trigger hit the frame in the back before it moved far enough to release the striker.  BTDT with that Galloway Precision trigger on the 2.0. .40 a few weeks back.

A little trimming/filing on the back of the Apex trigger and it's working great.  Not that light at 4.5 lbs. but that's almost 2 lbs. lower than it was and it's much crisper feeling.

Gonna try to get to the range next week.

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Got a 1.0 sub compact .40 that will be next.

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Did you grind the nub of the bottom of the 2.0 sear housing in order to fit it into the 1.0 frame?
Also did you have to do any mods to the frame?

I have thought about doing this before and wonder if you don't mind sharing the whole process to make it work.

Subscribed as "highly relevant to my interest" in updating my M&Ps.

Picture of the two sear housings.

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My old 1.0 frame had a notch formed in the bottom of the frame for that tab to fit into.  I test fitted it before even trying to put the trigger/trigger bar locking lug back in the frame.  Got it lined up and pushed it right down into place.  I did have some issues at the final install trying to get the sear housing hole, safety lever holes and frame holes lined up to insert/drive in the rear role pin.  I ended up inserting the pin from the right side of the frame to get it through most of the way and that made it easier to get the left side of the safety lever aligned.

If there had not been that dip/cut in the frame that seemed to be there for that tab I'd have had to do some work to see the purpose of the tab and whether or not removing it would affect anything.

I've already ordered parts to do a similar install/mod on a 1.0 sub compact .40.  If that frame is different I'll share the pictures.  I'll add those pictures to this thread when I do that swap.

Wish I taken a picture of the inside of the frame at the rear but I didn't think about it once the test fit showed the sear housing fitting in just fine.

No mods to the frame at all.  I did seem to have more alignment issues with the trigger pin (but then again, I couldn't find my Apex yellow slave pin either) than usual.  I'd say any alignment issues I had up front was due to the lack of a slave pin.

So far, just dry firing and working the slide back and forth I'm pretty happy with it.  Like I said, planing to do it again in a week or so when the parts come in (and that darn slave pin, too.)

Slow afternoon.  Pulled the sear housing out to take a picture of the frame and show the slot the tab on the bottom of the 2.0 sear housing seems to fit into pretty well.

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With more time, fresher eyes/mind, I think I also figured out the source of the alignment issues with the rear pin, 2.0 sear housing, frame and safety lever - on the 2.0 housing the spring/detent for the safety seems to be slightly different and it pushes the safety lever rearwards enough to affect alignment.  I had to sort of pull the safety forwards, at the right angle, to align the safety lever while pushing down on the back end of the sear housing while installing the rear pin.

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One other comment.  The 2.0 sear housing is really a snug fit side to side in this 1.0 frame.  It takes some time/effort to get it just right to slip down in the frame.  Once it hits that sweet spot in alignment /angle it pushes on down with finger pressure.  If I don't have things perfect it wants to catch on the right side and tilt every single time.  It can make me start to wonder if it will fit/insert into the frame and then suddenly if pops right in there.  When I get it perfect.

My frame may be different in some ways from other 1.0 frames.  I'll get a better idea of consistency in the next week or two when I get the parts for the sub compact .40 change over.

There are 2 types of 1.0 frames.

A- The early ones have no cutout for a manual safety and a sear block with a hole inside for the internal lock.
B- The late ones with manual safety cutouts like the one you have.

I tried a few years ago to fit a 2.0 sear block into a "A" frame and found that there was not cutout for the nub.

Did you use a 2.0 locking block or a 1.0 locking block?
(It looks like a 1.0, was wondering if a 2.0 block will fit, the 2.0 has a full length guide rail rather than the shortened one, the 2.0 locking block also has a steel nub on the bottom of it)

I reused the 1.0.  I've got a 2.0 on order with the 2nd 2.0 sear housing and trigger bar for the next swap attempt in the 1.0 sub compact frame.  When I do that some time this coming weekend/next week I'll see if the 2.0 locking lug will fit that frame.

I wondered the same thing.  If it fits I may order another one (2.0 locking lug) to swap into the 5" 9MM frame used in this thread.  When I do that I'll continue using this thread for the pictures/text.

For info - the older M&P 1.0 frames that don't have the cut outs or plugs in the frame for a thumb safety may have a different sear housing and frame.  Another member on the M&P Pistol forum tried to fit a 2.0 sear housing in his non safety/non plug frame and it would not fit.  The 2.0 sear housing is made different and will not fit down into the frame.

Don't have one myself.  Just saw the post on the forum with pictures of his sear housings.