M&P 9mm accuracy issues?
- Thread starter rcamp
- Start date
barrel crown
I used a dremmel tool attachment-cone shaped stone/grinder and wet/dry 400 grit sand paper, all BY HAND. NO power tools at all. The crown is critical to accuracy because it is the very end of the rifeling that the bullet is in contact with as it exits the barrel. There are different profiles at the end of a barrel, some are flat, some are flat and recessed and some are round. (the recessed style is to protect the muzzle crown) Regardless of the profile, the concern is where the lands and grooves stop and a slight taper opens up from the bore. This is easy to see. What is critical is that the crown is symetrical, with no imperfections at all. It must allow the bullet to exit without being upset by a burr or being sent wobbling because the crown is uneven.
First I noted the deepest part of the rifeling and worked the rest of it down to that point, making very sure it was square. This was a very small distance, just enough to bee seen with the naked eye. I hand turned the cone grinder bit and checked often. Then the 400 grit with oil to hone and smooth everything.
Be careful, you can ruin a barrel, but if you are careful and patient this can be done and if you have ridiculous sized groups, It wont hurt unless you are sloppy. This worked for me.
I used a dremmel tool attachment-cone shaped stone/grinder and wet/dry 400 grit sand paper, all BY HAND. NO power tools at all. The crown is critical to accuracy because it is the very end of the rifeling that the bullet is in contact with as it exits the barrel. There are different profiles at the end of a barrel, some are flat, some are flat and recessed and some are round. (the recessed style is to protect the muzzle crown) Regardless of the profile, the concern is where the lands and grooves stop and a slight taper opens up from the bore. This is easy to see. What is critical is that the crown is symetrical, with no imperfections at all. It must allow the bullet to exit without being upset by a burr or being sent wobbling because the crown is uneven.
First I noted the deepest part of the rifeling and worked the rest of it down to that point, making very sure it was square. This was a very small distance, just enough to bee seen with the naked eye. I hand turned the cone grinder bit and checked often. Then the 400 grit with oil to hone and smooth everything.
Be careful, you can ruin a barrel, but if you are careful and patient this can be done and if you have ridiculous sized groups, It wont hurt unless you are sloppy. This worked for me.
Rossi720
Member
I bought my M&P9 fs MPNxxxx back in 07 and have fired over 500 rds down range, after that I stopped counting. I shoot 3-4 " groups most times at 15 yrds. About 4 months ago my brother in law qualified with it for his CCW permit and the instructor had to double check due to all 30 rounds going through a 4" hole. He had never shot a M&P ever before. He then bought one and feels its not as accurate, was having hard time grouping. I asked to shoot a quick couple of rounds just to see and was still close to 4-5" group, He does not clean, break in or lubricating his weapons like I do. I love my M&P, trust it with my life and would never get rid of it.
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Maddmax
US Veteran
With so many guns being made/sold maybe it time for new tooling ??
dannybot
Member
I have had decent accuracy with my FS M&P's, just consistently low left, tight patterns. I was rifing the fence on Apex kits, but finally boke down and did the Burwell technique, and really lightened up the trigger. As far as objective measures, I don't have any. But my USPSA scores when from dead last to 50% at the first match after sear polishing. Also at the same match, I knocked down each steel with a single 115 gr round per target, down from from an average of 1.5 rounds per steel.
I am basically a Sig shooter but I wanted to try the M& P but my local gun shop had a used 40 SW at a good price. I bought it and a 9mm threaded barrel. Accuracy very good and no hiccups. Is the 40 accuracy no problem and the problem just lies with the 9?
Stay Safe!
Stay Safe!
From what I've read it seems to only affect the 9mm. Something about the locking block being not enough of a redesign from the .40 so the physics aren't quite what they need to be.
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Lee in Quartzsite
Member
Excuse me?? Where did you see that piece of information? I have four 9mm M&P's and every one is more accurate than I am. It's a tried and true design from day 1.
This target was shot by my wife...her 3rd magazine out of her new 9mm Shield from 15 yards. Bad shooting is seldom the gun's fault.
Arthury
Member
Look up the long long thread in m4carbine.net
and you will be able to get discussed issues.
I would say that there is a large difference between shooting my M&P9 and M&P45. I have even sent mine back to S&W and they said it was within their operating margins.
and you will be able to get discussed issues.
I would say that there is a large difference between shooting my M&P9 and M&P45. I have even sent mine back to S&W and they said it was within their operating margins.
Gran Torino
US Veteran
I'm waiting for APEX to get their Apex/Barstow barrel into production and I plan on picking one up.
Arthury
Member
Check these
I'm assuming you are shooting jacketed bullets ... make sure the rifling on your M&P9 are not fouled by copper.
If rifling is pretty much filled up, there's not enough grip on the bullet so you are essentially shooting on smooth bore (with no rifling), ending up with a highly unstable bullet. Same thing if you are shooting lead.
Your regular Hoppe's #9 don't remove lead or copper fouling much.
I'm assuming you are shooting jacketed bullets ... make sure the rifling on your M&P9 are not fouled by copper.
If rifling is pretty much filled up, there's not enough grip on the bullet so you are essentially shooting on smooth bore (with no rifling), ending up with a highly unstable bullet. Same thing if you are shooting lead.
Your regular Hoppe's #9 don't remove lead or copper fouling much.
gamma72
Member
How much ammo would it take to foul up the barrel?
I have a 1911 with over 4k of 45 acp and a M&P9 with over 2k through it with mostly plated bullets. So far i dont see any issues on either pistol with regards to accuracy or copper/lead in the barrel rifling.
Hey Lee...
I usually try to stay positive, but geezzzz, please understand that there are experienced shooters posting about the accuracy issues of the full size M&P 9mm. This is real.
Congrats on having 4 guns that shot consistently. Some of us aren't experiencing that. I received a new barrel for mine, purchased in May, and went from unable to group, unable to keep 5 shots on the paper at 25 yds (benched and bagged), to geting 4-5 inch groups at 25 yds. I still get the occasional unexplained flyer. And anyone who wants to get pissy about shooting out to 25 yds, well, I'm not going to try to explain it to you, you don't want to hear it. (For some shooters, that is the Gold Standard of measured accuracy. That doesn't mean we are practicing to shoot defensively at 25 yds, unless required during a drill or shooting station).
As far as proven design.... It is my understanding that there were changes made to the barrel production when the compact was introduced. So if that is true, the proven design was altered.
As far as QC, my son is an engineer for Micro VU, which makes optical scanning equipment for QC inspection of parts put into production. Used in many, many industries. This is what S&W needs, to pull parts out of a production run to check if they meet the specs of the "Proven Design" benchmark. There are a lot of variables that can change during a production run of a part.
What I can tell you is that the replacement barrel that I received has a much tighter fit to the slide. Hard to really tell how it is interacting with the locking block.
Bottom line, it shoots better.... dramatically better. I don't think I changed very much while I waited for the gun to return from S&W. Infact, I did not fire a single round in any handgun while I awaited its return.
Cw
I usually try to stay positive, but geezzzz, please understand that there are experienced shooters posting about the accuracy issues of the full size M&P 9mm. This is real.
Congrats on having 4 guns that shot consistently. Some of us aren't experiencing that. I received a new barrel for mine, purchased in May, and went from unable to group, unable to keep 5 shots on the paper at 25 yds (benched and bagged), to geting 4-5 inch groups at 25 yds. I still get the occasional unexplained flyer. And anyone who wants to get pissy about shooting out to 25 yds, well, I'm not going to try to explain it to you, you don't want to hear it. (For some shooters, that is the Gold Standard of measured accuracy. That doesn't mean we are practicing to shoot defensively at 25 yds, unless required during a drill or shooting station).
As far as proven design.... It is my understanding that there were changes made to the barrel production when the compact was introduced. So if that is true, the proven design was altered.
As far as QC, my son is an engineer for Micro VU, which makes optical scanning equipment for QC inspection of parts put into production. Used in many, many industries. This is what S&W needs, to pull parts out of a production run to check if they meet the specs of the "Proven Design" benchmark. There are a lot of variables that can change during a production run of a part.
What I can tell you is that the replacement barrel that I received has a much tighter fit to the slide. Hard to really tell how it is interacting with the locking block.
Bottom line, it shoots better.... dramatically better. I don't think I changed very much while I waited for the gun to return from S&W. Infact, I did not fire a single round in any handgun while I awaited its return.
Cw
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Nakanokalronin
Member
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Well I got my FS M&P 9 back from S&W today for the second time and the paperwork now says that the barrel has been replaced and meets spec. We'll see soon enough if the problem has been corrected.
budrichard
Member
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"As far as QC, my son is an engineer for Micro VU, which makes optical scanning equipment for QC inspection of parts put into production. Used in many, many industries. This is what S&W needs, to pull parts out of a production run to check if they meet the specs of the "Proven Design" benchmark. There are a lot of variables that can change during a production run of a part."
Anyone with any QC credentials will tell you that a study of the defective items and an on-site audit/examination of the process producing the item are required to make ANY assertion about what is required to fix the problem.-Dick
Anyone with any QC credentials will tell you that a study of the defective items and an on-site audit/examination of the process producing the item are required to make ANY assertion about what is required to fix the problem.-Dick
Regarding QC...
Agreed! Simply dealing with each gun sent in and resolving it's issue does not address the source of the problem. Only S&W has the statics of how many sent in, how resloved.... and then take that info and decide how to solve the problem in manufacturing and production. Otherwise they will continue to fix guns until the cows come home.
Cw
Agreed! Simply dealing with each gun sent in and resolving it's issue does not address the source of the problem. Only S&W has the statics of how many sent in, how resloved.... and then take that info and decide how to solve the problem in manufacturing and production. Otherwise they will continue to fix guns until the cows come home.
Cw
Martimus
US Veteran
Some of the information presented on the suspected accuracy issues has been quite interesting.
Several months ago I picked up a M&P9 for a screaming deal at a local pawn shop (scared me that I could actually find a deal at this particular pawn show. In hindsight I'm starting to wonder if the screaming deal was offered for a reason?). Took it to the range and found that at 15 yards it was shooting a good 3-inches to the right of POA. Quadruple checked my grip, my stance, tried closing one eye, spent a couple hours with an instructor I know, etc. I probably tried every logical and illogical thing I could possible try to determine the cause. Tried alternating with another pistol but while the other pistol shot to POA, the M&P9 shot 3-inches to the right of POA.
I replaced the stock sights on the M&P which marginally improved things but I was still shooting to the right of POA. Out of curiousity and frustration, I ordered a replacement M&P9 barrel from Brownells. Not exactly what I wanted to be spending my limited savings on, but I needed to know what was going on. Installed the new barrel and went to the range. My M&P is now shooting at POA. Re-installed the old barrel in the M&P - 3-inches to the right of POA. Replaced the new barrel - shooting at POA.
While this experiment was by no means scientific and is certainly not conclusive, I suspect that I'm going to keep the new barrel in my M&P.
In looking at the rifling of the old barrel I can't see anything out of the ordinary. That said I'm no gunsmith so I make no guarantees that I'd even know what to look for.
Several months ago I picked up a M&P9 for a screaming deal at a local pawn shop (scared me that I could actually find a deal at this particular pawn show. In hindsight I'm starting to wonder if the screaming deal was offered for a reason?). Took it to the range and found that at 15 yards it was shooting a good 3-inches to the right of POA. Quadruple checked my grip, my stance, tried closing one eye, spent a couple hours with an instructor I know, etc. I probably tried every logical and illogical thing I could possible try to determine the cause. Tried alternating with another pistol but while the other pistol shot to POA, the M&P9 shot 3-inches to the right of POA.
I replaced the stock sights on the M&P which marginally improved things but I was still shooting to the right of POA. Out of curiousity and frustration, I ordered a replacement M&P9 barrel from Brownells. Not exactly what I wanted to be spending my limited savings on, but I needed to know what was going on. Installed the new barrel and went to the range. My M&P is now shooting at POA. Re-installed the old barrel in the M&P - 3-inches to the right of POA. Replaced the new barrel - shooting at POA.
While this experiment was by no means scientific and is certainly not conclusive, I suspect that I'm going to keep the new barrel in my M&P.
In looking at the rifling of the old barrel I can't see anything out of the ordinary. That said I'm no gunsmith so I make no guarantees that I'd even know what to look for.
