Is there a resource for the revisions M&P 1.0s went through BEFORE the 2.0 redesign?

[Echo40]

Is there a resource for the revisions M&P 1.0s went through BEFORE the 2.0 redesign?

After purchasing a M&P40c 1.0 recently I was surprised to learn that the M&P series underwent some revisions prior to the release of the M2.0 models, but I've been unable to find any resource for information in regards to when these revisions were implemented or what all of them were.

I've read reports of a number of revisions both big and small such as, but not necessarily limited to:

• Added tear drop relief beneath firing pin hole to mitigate primer flow. (Confirmed)
• Removed "Stainless" stamp from M&P slides. (Confirmed)
• Replaced Novak sights with a stepped style designed to facilitate one-handed slide racking. (Confirmed)
• Replaced blue 15lb recoil springs with yellow 17lb recoil springs in M&P40 pistols. (Citation Needed)
• Improved magazine followers to address nosedive malfunctions and improve feeding. (Confirmed)
• Improved rifling twist rate from 1:16 twist to 1:10 twist on M&P9 Barrels. (Confirmed)
• Replaced Melonite® salt-bath nitride FNC with in-house Armornite® treatment for improved QC. (Confirmed)
• Upgraded Striker Spring Assembly with improved durability. (Citation Needed)
• Improved sear housing to mitigate sear flutter and striker drag/light primer strikes. (Confirmed)
• Modified sear/trigger bar for a smooth trigger pull and audible/tactile reset. (Confirmed)

Has there ever been any official documentation, online article, or even a thread detailing/compiling the revisions that the M&P 1.0 pistols underwent prior to the introduction of the 2.0 models?
If not, then perhaps we can make this thread into such a resource. Any information on the subject would be greatly appreciated.

 

[ken158]

You can Google Shield 1 vs 2 and get the answers you seek. This topic was discussed at length when the 2.0 was introduced and doubtful you would get much interest in much of a re-run of those discussions. Grip texture and trigger were the main changes best as I recall. I just put an Apex kit in my version 1 and solved any issue I had with it.

 

[Echo40]

I'm asking what revisions were introduced prior to the release of the 2.0 redesign during the production run of the 1.0 series.

The revisions added WITH the 2.0 redesign is well documented, what I'm looking for is information in regards to what revisions were made to the 1.0 models BEFORE the 2.0 redesign.

 

[Saudade]

I don't know of any "single" resource for the rolling changes. Here's what I do know. Again, there's no specific date or serial number to mark when these changes occurred. I assume S&W simply used the new parts when the old ones ran out.

1. Sear Housing. The early ones had provisions for a internal lock. You could use a special "key" to prevent the trigger from operating. Much like the S&W revolvers with the lock.

It looks like this:



Then the sear housing changed (provides for a manual safety). it looks much like the one in yours except the sear plunger and return spring were 1/16" in diameter. Apex Tactical has remarks on their trigger kits requiring the "updated" sear housing with the 1/8" diameter plunger and spring to prevent sear flutter. So the final sear housing uses a 1/8" sear plunger and spring.

2. The trigger bar changed. Early ones has an "S" stamped inside the bar. The updated ones have an "H". More on this next.

3. Slide stop. The inside of the right side that rides along the trigger bar was flat. This made for the weak (if any) reset. The "gen 2" slide stops had the end bent out a bit to put more tension on the trigger bar once "disconnected" to make for a more audible and tactile reset. Gen 3 has a "bump" to put more pressure on the trigger bar. The "H" trigger bars improved the reset when used with Gen 3 slide stops (some improvement with Gen 2). Some folks felt it was still pretty weak.






4. Barrel twist rate (may only apply to 9mm). The 9mm barrels had a 1:16 (I think) twist rate originally. S&W switched to 1:10. I don't know if the .40S&W models had a twist rate change.

5. Not sure of this was a "production change" but the "plain" M&Ps had a MIM sear. The Performance Center (PC) ones had the PC machined sear. Apex Tactical has a picture of the different sears (compared to their own).

For a reference point, my 2013 full size and compact has the "S" trigger bar, Gen1 slide lock, 1:10 barrels, 1/8" sear housing. I did update them both to Gen 3 slide stop and "H" trigger bar, but later put 2.0 triggers in them.

 

[Saudade]

Ah, forgot to include:

To accommodate the internal lock, the frame had a "hole" for the key. Note the lack of the little blocks where the manual safety goes.

Many of the PC ones had the hole with a plug in it with the "updated" sear housing with the PC sear.

 

[Tom S]

Love these older threads, I'm new here and found most all info on my Gen 1 M&P .40S&W in the threads here so I haven't had to ask any questions yet. But this one really made my day when I read that what my calipers said was indeed the case,that the last sear upgrade had the 1/8" sear body already installed in mine. Looked for a month or so and bought a comp sear housing for the Apex Forward sear trigger upgrade with the 1/8" sear spring.. low and behold i now have a complete spare sear housing with the larger sear spring. Thanks! Love the forum. And my first post!

 

[Saudade]

Welcome to the forum!!

 

[Tom S]

Welcome to the forum!!

Thank you, just looking at some older post trying to learn about my gen 1 .40s&w.

 

[fiasconva]

When did they change the twist rate and was it to improve accuracy?

 

[WR Moore]

OK, the original twist was the standard S&W .38/.357/9mm twist of 1-18.75. I'm not sure why the twist changed, there was some talk of it due to gamesmen who shot 147 gr bullets at low velocities to just barely make power factor. My experience with several S&W 9s of various models was that the twist rate didn't effect accuracy with standard velocity/+P velocity ammo at typical ranges.

Swapping electrons with Randy at Apex, he alluded to some complex mechanical thing helping accuracy. I didn't buy that, didn't keep the email, seemed mechanically insignificant.

IMHO, it had more to do with the ill fated attempt to compete for the DOD service pistol contract. 1-10 is pretty much the world standard 9x19 mm twist.

There were two revisions to the extractor. One was marked L the latest and greatest marked P for the designer.

 

[mrshyvley]

Some years back I bought two Police Trade-in S&W M&P 40 1.0 pistols pretty cheap, that I later upgraded both to .357 Sig.

These were both early pistols that had the 1/16" springs, key locks, older striker assembly, etc.

Here's the parts I used to upgrade them.
They've been rock solid reliable pistols, and I got them cheap enough the upgraded parts still kept the money I have in them low.

M+P40 1.0 Pistols Upgraded
1. Ser# MPC104x
2. Ser# MPH451x

M+P40 1.0 UpgradeParts
1. Smith & Wesson Sear Housing Block with 1/8" spring, and without
Integral Lock and Magazine Safety S&W M&P,
M&P Compact 9mm Luger, 357 Sig, 40 S&W
- Product #: 546264 Manufacturer #: 390900000 UPC #: 197706546264

2. Smith & Wesson Striker Assembly S&W M&P, M&P Compact 9mm Luger,
357 Sig, 40 S&W Stainless Steel
- Product #: 466044 Manufacturer #: 393790000 UPC #: 197706466044

3.Smith & Wesson Recoil Guide Rod Assembly S&W M&P 9mm Luger, 357 Sig, 40 S&W
- Product #: 568944 Manufacturer #: 279740000 UPC #: 197706568944

=============== After upgrading barrel to OEM S&W .357 Sig Barrel
4. * Apex Tactical Failure Resistant Extractor S&W M&P Steel Melonite
- Product #: 739146 Manufacturer #: 100-068 UPC #: 856008005154

* NOTE:Got this Extractor to fix problem with the old OEM extractor
leaving the spent brass in the chamber of both pistols and jamming them.
So I upgraded to the Apex extractors and the problem went away with both pistols.

to an OEM S&W .357 Sig Barrel.