Questions about a used M&P40

dazlin · #1 03-04-2020, 10:57 PM

Hi,
I bought a police turn-in M&P 40 (1st gen) recently. After disassembly and cleaning I noticed a couple of things that were disturbing. Perhaps others can enlighten me if these are problems that I need to resolve before firing it?

Problem 1: There is a patina-like coating on several of the metal surfaces. It resists removal. Unfortunately, I can't determine if it is a real patina, fouling or rust. Attached pix show an example on the locking block.

Problem 2: After cleaning the barrel, I discovered some odd patches just after the end of the chamber. I can't seem to determine if this is normal or not. It doesn't look like fouling because it is too regular. Under a magnifier there appears to be parallel striations in each patch extending from one rifling groove to the next. But they are not consistent as they only appear at every other pair of rifling grooves. They are discolored but I cannot figure out if this is normal or not for an M&P barrel. Here are some pictures...

Rastoff · #2 03-05-2020, 01:22 AM

All patina is rust. Patina is only bad if there is pitting. I don't see any pitting on your gun.

I just looked a the bore of my .40S&W. It looks just like yours.

Go shoot your gun and enjoy angst free.

spricks · #3 03-05-2020, 01:52 PM

Looks like normal wear to me. Hard to even guess how many rounds have been through it. I would go ahead and make sure it functions without any problems....I'm thinking it will be good to go!

spricks

Boogs · #4 03-05-2020, 04:26 PM

Barrel looks typical.

Hard to determine if it is rust, but as it was already stated, pitting is your concern.

I am definitely one that would go over a used pistol with a magnifying glass-- that is why I abstain from purchasing them

If it is going bang, enjoy it!

BillyMagg · #5 03-06-2020, 10:50 AM

Quote:

Originally Posted by dazlin

Hi,
I bought a police turn-in M&P 40 (1st gen) recently. After disassembly and cleaning I noticed a couple of things that were disturbing. Perhaps others can enlighten me if these are problems that I need to resolve before firing it?

Problem 1: There is a patina-like coating on several of the metal surfaces. It resists removal. Unfortunately, I can't determine if it is a real patina, fouling or rust. Attached pix show an example on the locking block.

Problem 2: After cleaning the barrel, I discovered some odd patches just after the end of the chamber. I can't seem to determine if this is normal or not. It doesn't look like fouling because it is too regular. Under a magnifier there appears to be parallel striations in each patch extending from one rifling groove to the next. But they are not consistent as they only appear at every other pair of rifling grooves. They are discolored but I cannot figure out if this is normal or not for an M&P barrel. Here are some pictures...

As our good friend Rastoff points out, you're good to go, nice pictures by the way...

I'm a little disappointed in some aspects of my own M&P .40 as far as fit and finish, it runs like a freight train though...

sheepdawg · #6 03-06-2020, 10:54 AM

See what it looks like after a good session at the range.

dla · #7 03-06-2020, 01:08 PM

The reamer they cut the leade with was a little rough IMO, but it would have zero effect on accuracy.

I say throw it in the dishwasher to clean the Cop boogers out of it, gently/lightly lube it, and then shoot the snot out of it for the next 20 years. Then post on how it is doing.

Boogs · #8 03-06-2020, 03:14 PM

Quote:

Originally Posted by dla

...I say throw it in the dishwasher to clean..

Is this a thing?

seldon14 · #9 03-06-2020, 04:35 PM

Quote:

Originally Posted by Boogs

Is this a thing?

Depends on if you are married, or want to stay that way.

dazlin · #10 03-09-2020, 12:51 PM

Thanks, everyone. I'll put some rounds through it and see how it goes.

BTW, the pictures were taken with my phone using the micro-focus mode. Adjusting the lighting until it looked good was the only other factor. The annotations and cropping come from the Snagit screen capture tool's editor.

gnfrk · #11 03-27-2020, 09:04 PM

Not sure if that is patina or not, I do know that if someone used a copper srubbing pad or copper brush to clean with you can get that "patina" look as the copper is soft enough to leave a little residue on the surface, just a thought

hardluk1 · #12 03-28-2020, 11:53 AM

I don't see a thing unique aboput your photos to a good used M&P 40sw pistol except maybe a better lubes could have been used and it would have reduced the yoiur Patina what I'll call buffing of metal caused by the slides rails barrel lugs locking and unlocking over the years !! My daughter bought 4.25 40 with a thumb safety about 7 or 8 years ago for a house gun . She hated the trigger pull so I added a apex fss trigger kit and striker block kit and shoot about 6000 practice rounds threw it between her and her husband and son . She wanted to trade it for a 9mm she could carry easier so its filled her wish and the M&P 40 is mine now . Only change I made before shooting it was to add a heavier than gen 1 stock 20lb recoil spring . Glock recoil spring work in both 4.25 and 5" m&p's . Current 2.0 40sw use 20lb spring . Good pistol and a very good shooter with 165gr home loads .

dazlin · #13 08-05-2020, 10:01 PM

Just to close the loop... Took it out to the range and put a box of range ammo through it. Ran like a champ. A bit snappy. Nice trigger (wonder if it had a trigger job when it was a police gun?).
Now I just need to get new sights as the tritium on it is dead.

Thanks, all.

BillyMagg · #14 08-08-2020, 11:55 AM

Quote:

Originally Posted by dazlin

Just to close the loop... Took it out to the range and put a box of range ammo through it. Ran like a champ. A bit snappy. Nice trigger (wonder if it had a trigger job when it was a police gun?).
Now I just need to get new sights as the tritium on it is dead.

Thanks, all.

Thank you for closing the loop,, the .40 is a bit snappy, but my favorite auto pistol round, my M&P .40 has challenged me a bit. I don't get the kind of groups I would like, though at 15 yds I did have 3 out 10 in the same ragged hole? this was off a bag 0n the old truck hood, lol.

MyDads38 · #15 08-12-2020, 10:44 PM

I bought a PD trade in M&P 40 a few years ago, very happy with mine. 40 isn't my favorite caliber, but it shoots as well as my FS 9 & 45. Factory or reloads, doesn't matter-shoots it all with no issues. Shoot, clean, repeat....and ENJOY!! :-)

1sailor · #16 08-13-2020, 07:06 PM

To the OP. If you find it a bit too snappy you can always drop in a factory 9mm barrel. Must be more than a dozen members have done it (including me). Great for target practice.

Jason Demond · #17 08-13-2020, 10:20 PM

The .40 M&P does the .40 caliber really well, and is a joy to shoot compared to some of their off brand counterparts.

kmyers · #18 08-15-2020, 02:32 PM

The M&P .40 here is a favorite for both of us

Great caliber and one I like a lot and an added bonus is that you can still find ammunition for it. We have 6 pistols in the caliber.

DHart · #19 08-23-2020, 07:32 PM

M&P40 - one of the best defense pistols you can buy. Shooting .40S&W 180 gr premium defense loads with this pistol is soft and sweet! 155 gr and 165 gr can feel a little harsh compared to the 180 gr. I like the 180 gr the best.

M&P40 Compact is very sweet, as well! I've had my M&P40 Compact since they were first released.... been a LONG time! Carried a lot, shot a lot. Love it.

dazlin · #20 09-18-2020, 11:14 PM

Quote:

Originally Posted by DHart

M&P40 - one of the best defense pistols you can buy. Shooting .40S&W 180 gr premium defense loads with this pistol is soft and sweet! 155 gr and 165 gr can feel a little harsh compared to the 180 gr. I like the 180 gr the best.

Well, my first pistol was a 40... a 1st gen Sigma. After it self-destructed with a case head separation, S&W replaced it with a new 2nd gen Sigma 40. Still have it and even used it in some competitions.

So far, the M&P40 feels good with its new night sights and a gun light.

Dan