M&P 45 Question

[threedogdad]

Hello gang,

I have an M&P 45 (mid-size model) that I have used as my dedicated outdoors gun since 2010. To date it has 7,336 rounds through it and until recently has proven both reliable and very shootable.

Over the past 500 rounds however (roughly since the beginning of this summer) a couple of problems have developed and I would like to ask for your assistance.

1. The slide frequently fails to lock back after the last round. This has occurred in each of my three magazines and does not seem to be specific to any particular brand or type of ammunition.

2. The slide has started to "auto-forward" when inserting a loaded magazine. It did not do this when new, but does it every single time now.

3. When shooting hotter ammo (not necessarily just +P) I frequently get brass to the face. This never happened until recently.

I changed out my recoil spring roughly 2,400 rounds ago and have always kept the pistol clean and well lubricated.

I'm an avid shooter, but not a professional shooter or gunsmith. But I am a serious and dedicated long distance hiker and wonder if this might be the source of my problems. This pistol has seen literally thousands of miles in rough country in all kinds of weather and in all four seasons. Snow, rain, mud, heat, dust, dirt, etc. I have taken a few spills over the years, but nothing comes to mind as far as an occasion when the pistol might have taken a direct blow. Very well could have happened; I just don't recall anything specific. Because of these recent problems however, I have kept the M&P strictly on the range this summer and have been toting around a favorite old DA revolver in the mountains instead, but the weight makes me reluctant to do this as a long-term fix.

Any thoughts? Do you see these as routine maintenance issues or might something else be going on here? Should I consider looking for a replacement? I'm not asking the question this way as an excuse to buy a new pistol. I simply won't carry an unreliable pistol into the wilderness. But I don't know at what point I can reasonably say to myself--"this pistol has outlived its usefulness." I know Todd has successfully put some 50,000 rounds through an M&P and my total is far less, but as far as miles and exposure to the elements I'm beginning to have doubts and therefore turn to you for advice.

Thank you in advance.

[irascible_joe]

1. My first impulse would be to clean the magazines and replace the mag springs. If the follower isn't getting all the way to the top of the tube fast enough and with enough force, you'll get failures to lock back. After 7k rounds spread across only 3 magazines, they've had a fair number of load/unload cycles.

2. I'm not an M&P expert, but I believe it's fairly common for the auto-forward to happen more frequently over time. If it bothers you, a new slide stop assembly is less than $20.

3. I don't have any M&P-specific experience, but the generic advice is to check your extractor for wear/chips and sufficient spring tension, and make sure the ejector isn't worn or damaged. Or maybe your M&P has just been hanging around recent-production Glocks too much

Good luck!

[RJ]

I can only contribute that my Oct 13 build M&P9 FS with 1,570 rounds pretty much has auto forwarded from new.

I tend to smack the magazines in with some enthusiasm.

Looking forward to what the experts here think.

[KeeFus]

Hello gang,

I have an M&P 45 (mid-size model) that I have used as my dedicated outdoors gun since 2010. To date it has 7,336 rounds through it and until recently has proven both reliable and very shootable.

Over the past 500 rounds however (roughly since the beginning of this summer) a couple of problems have developed and I would like to ask for your assistance.

1. The slide frequently fails to lock back after the last round. This has occurred in each of my three magazines and does not seem to be specific to any particular brand or type of ammunition.

2. The slide has started to "auto-forward" when inserting a loaded magazine. It did not do this when new, but does it every single time now.

3. When shooting hotter ammo (not necessarily just +P) I frequently get brass to the face. This never happened until recently.

I changed out my recoil spring roughly 2,400 rounds ago and have always kept the pistol clean and well lubricated.

I'm an avid shooter, but not a professional shooter or gunsmith. But I am a serious and dedicated long distance hiker and wonder if this might be the source of my problems. This pistol has seen literally thousands of miles in rough country in all kinds of weather and in all four seasons. Snow, rain, mud, heat, dust, dirt, etc. I have taken a few spills over the years, but nothing comes to mind as far as an occasion when the pistol might have taken a direct blow. Very well could have happened; I just don't recall anything specific. Because of these recent problems however, I have kept the M&P strictly on the range this summer and have been toting around a favorite old DA revolver in the mountains instead, but the weight makes me reluctant to do this as a long-term fix.

Any thoughts? Do you see these as routine maintenance issues or might something else be going on here? Should I consider looking for a replacement? I'm not asking the question this way as an excuse to buy a new pistol. I simply won't carry an unreliable pistol into the wilderness. But I don't know at what point I can reasonably say to myself--"this pistol has outlived its usefulness." I know Todd has successfully put some 50,000 rounds through an M&P and my total is far less, but as far as miles and exposure to the elements I'm beginning to have doubts and therefore turn to you for advice.

Thank you in advance.

Sounds like mag springs are the issue. Call S&W CS, they will replace them free of charge as they've had documented issues with M&P 45 mag springs.

http://pistol-forum.com/showthread.p...hlight=springs

I've had mine since it was issued in November 2011. It auto forwards with loaded magazines.

Brass to face...I'm guessing but is your ejector loose in the housing? Otherwise I'd try replacing the extractor spring and maybe the extractor.

http://www.speedshooterspecialties.c...oducts_id=1042

[Wayne Dobbs]

I would say that instead of new magazine springs, just replace those mags. Once a magazine has processed that many rounds, it's probably eligible for retirement.

Brass to the face is a sign of marginal extractor performance first. The extractor is likely losing full control of the fired case on the way out of the chamber resulting in irregular presentations of the case to the ejector. To keep things simple (and less expensive), replace the extractor spring first and see what you get.

Auto forwarding is a common trait of the polymer framed pistols.

[rsa-otc]

I have a M&P45 as well with approximately 20000 rounds through it in the last 4 to 5 years. I have yet to feel the need to replace the recoil spring, but then I mainly shoot mild to mid range power ammo. Those 20000 rounds are spread over 6 mags. Early on their springs were replaced with the factory updated black springs and are going strong at this point.

While auto forwarding is a common trait of polymer Pistols, since you were not experiencing this until recently it may be a by product of the weak magazine springs. Not only are you having failure to lock back issues, when it does lock back the slide lock may not be fully engaging the notch and the momentum of inserting the magazine may be releasing the partially engaged slide lock. This may go away when you replace the magazine springs or the magazines themselves.

With regards to the ejection issues carefully inspect the extractor for damage, undue wear and or dirt trapped under the extractor. If the extractor appears fine clean the notch it sits in and replace the spring. Otherwise replace the extractor as well. If you choose to do this yourself remember to drive the extractor roll pin out from the top of the slide downwards and replace it in reverse. Otherwise you may have issues with the extractor retaining pin working it's way out.

[threedogdad]

All,

Many thanks for all the helpful advice. I'll call S&W on Monday for some new mag springs and go from there.

[Salamander]

I bought my M&P 45 (full size) as a hiking/backcountry gun also, but retired it from that role pretty quickly. It's currently used as a range gun only. There were two issues:

1) Beginning at 300 rounds, the gun experienced three FTE's and two FTF's in the next 100 rounds. Replacing the factory extractor with an Apex FRE resolved this issue, and there have been no stoppages since then.

2) After taking care of the above I loaded a few magazines, didn't use them for a couple of weeks, and then emptied the defense ammo before a range trip. In three of four magazines, the follower failed to move all the way up, and the last two or three rounds just rattled around loose inside the magazine. Subsequent tests indicated that loading for as short as overnight resulted in similar spring binding. S&W customer service replaced all four mag springs no questions asked. The original springs (mid to late 2012 manufacture) were painted black, and were of two different designs; the new replacement springs (spring 2014) are painted light blue. The magazines have functioned well since the spring replacement.

Mine auto-forwards fairly frequently but generally locks back OK on the last round.

While I probably don't cover the kind of miles you're describing, I do routinely go 10-20 miles at a time in wilderness areas and from October to April rain is frequent. This particular gun also saw some use in a large coastal dune environment where salt spray and windblown sand are not unusual. However I'm going to attribute my issues to particular parts rather than weather, and as described above the fixes were pretty simple.

Since the initial issues I've been carrying two different HK's in the backcountry in sometimes much worse weather than the M&P ever saw, and both of those guns have been flawless. When I head to Oregon next week I may bring a Glock 19 which has been perfect at the range just to give it a little tougher test. Since all three of those guns have been reliable through up to several thousand rounds each and they are all more compact and a little lighter than the M&P, as of now I see no reason to switch back and am debating whether to keep the M&P or sell it.

[KeeFus]

The original springs (mid to late 2012 manufacture) were painted black, and were of two different designs; the new replacement springs (spring 2014) are painted light blue. The magazines have functioned well since the spring replacement.

The blue ones now come with a new follower. In this pic you can see the difference in the old and new follower.