I recently purchased a M&P 15 Sport. I have had some problems with the gun jamming. I am using the stock pmag and bushmaster 30 round magazines that came with the gun. I am shooting Remington PMC factory .223 ammo purchased from Walmart. I have fired the gun about 80 -100 times. If the bolt and receiver are not well lubricated with Breakfree CLP or Rem oil (or other such lubricant), the gun will jam. Specifically, the gun will lift the cartridge from the magazine but will not push it into the chamber. The cartridge will get caught between the bolt and the chamber. The cartridge case will be well dented near the shoulder so bad the cartridge will have to be discarded. This problem happened about 1 in 3 rounds when the gun was first fired. It now happens about 1 in 8 times. Several shooters of ARs at my gun club have observed this problem with my rifle and tell me the gun just needs to be shot in rather than sent back to Smith and Wesson for repair. The fired cartridge cases have observable scratches on the case necks and the case bodies. I am interested in getting readers opinions and advice. Also, what 3 shot groups are reasonable at 100 yards? Thanks in advance.

You answered your own question right there. AR's function better wet. Lube the bolt , and BCG rails.

Also, the 15-Sport is a tad over gassed. Install an "H" or "H2" buffer and see if it cures your harsh ejection problem.

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-John

Spikes ST-T2 buffer and a blue Sprinco spring. Run it wet.

double post lol

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CLEAR!

Get a heavier buffer when you can....


Oil the cam too

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CLEAR!

Where do your ejected rounds land ?

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Light, Accurate,Versatile M&P

The ejected cases land in a very small area, 3-4 ft diameter circle, about 10 feet from the shooting position. The cases land to the right rear from where I am shooting- at about a 4 o'clock position if the muzzle was at 12 o'clock. I am shooting off a concrete bench rest using a padded blanket over the concrete with the rifle being rested on sandbags for stability.

Where does the bolt come to rest against the cartridge? Behind it, still trying to push it up the ramp, or does it override the base and come to rest against the body of the case?

Is the gas key on your bolt carrier loose?

Is your gas tube loose where it connects to the front sight base?

Is the gas tube off center or not coming back far enough in the upper receiver? Compare with pictures of other ARs on a google image search.

Have you tried a different brand or lot of ammo?

Are all three gas rings present on the bolt? Any deformation or damage?

Any obstructions in the receiver extension, aka buffer tube?


Ignore the "advice" above to get a heavier buffer until you find out the real cause for your malfunction.

Wow...I just posted the same thing up. Having the same issues. Im thinking it's possible I didn't lube the bcg wet enuff to my rifles liking.

I would also add to the above make sure the gas rings are not aligned the gaps should be staggered and spray some lube in the mags as well.

AR's like to be run wet. Not dripping, but close.

The alignment of the gas ring gaps doesn't matter at all. Also, lube in the magazines not only collects grime, it can be dangerous. If too much lubricant is transferred to a case body before it chambers, this condition can drastically increase rearward force on the bolt during firing, leading to damage or personal injury.

I am not talking dripping wet. I place a very small amount to help the plastic carriage inside ride smooth especially with a new mag I learned that trick in bootcamp from my senior DI and I haven't had any problems with it either in the Corps or now. You don't use any more lube than what you would spay on a cloth to dust with

I have 4 mags two from s&w and two from colt for the 16 and they all was a little sticky until I did that and after 1200 rounds still no problems with the mags or oil on the rounds.

Here is a interesting article on mags:
Extreme Duty AR-15/M-16 Magazines from D&L Sports, Inc.

Yes unfortunately dated practices in the military build a lot of bad habits about firearms maintenance, and oil in the magazines is just one of them. The gas ring alignment myth is another.

One of my Drill Sergeants in basic told me he put CLP on his ammunition to make sure the rounds fed well. Just because it came out of a DIs mouth doesn't make it good advice.

I agree with you about believing everything out of a DI's mouth lol but in the article I posted I was having the carriage getting cocked on me like in the top left picture and that did stop that problem and it was the same thing in boot camp. But at the same time I do see your point about over lubing especially the dirt and getting excessive oil on the rounds is a big no-no.

Gas ring disalignment is still taught during assembly and cleaning in my last 3 duty stations over the past 16 yrs. Though I've read this argument on every major forum.
If this is the case, it's neither rite or wrong.

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Light, Accurate,Versatile M&P

Who is this that's teaching to stagger the gas ring gaps? Probably guys who were told the same thing at their last duty station, and don't know enough to question it.

Align your gas ring gaps and shoot the AR, try to create a malfunction. Let me know when you do. I won't be holding my breath.

directly out of the S & W manual:
Assemble your rifle in the reverse
order that you took it apart.
• Make sure that the gas-rings
on the bolt are NOT aligned
when reassembling. (Figures
64 & 65)
• Lubricate all metal parts by
wiping them with a cloth
dampened with a high quality
firearm oil. Remove excess
oil. Leave a light film of oil on
all metal parts of your rifle -
inside and out.
• See page 29 for details regarding the piston driven variation
and its unique instructions

And you think S&W is the authority on ARs? They are just repeating the same myth, started by the same sources, we've been talking about.

Again, align the gas rings and shoot the thing. Stop believing rumor and test it yourself.

CATAMs instructors, aka military gunsmiths.
Combat Arms Training And Maintenance.

As Per AF TO/ARMY TM
I will try and find a copy to see if it's still in there.

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Light, Accurate,Versatile M&P

Believe me that's not nearly as impressive as you intended it to be. I've known several military "gunsmiths".

I have emailed S & W and asked them why? I am interested in the response .It should be interesting.

Chapter 5
Pg. 56 (5-12)
Step 3.
Figure 17

Lots of good info for all of us. this is a joint pub.

http://www.google.com/m/url?client=m...XVCfcm2skFa5cA

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Light, Accurate,Versatile M&P

Dragon, please don't act as if were on m4carbine.
I posted the spelling for non mil types who are reading.
It was not ment to say or show anything more than what it is.

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Light, Accurate,Versatile M&P

What's all the fuss? It's a sport, it's not a real AR, of course it's going to jamb!

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Rod
M&P 22A, 40c, 15A, 15-22

J/K, I just wanted to post that for the dramatic effect that I was thinking it would have

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Rod
M&P 22A, 40c, 15A, 15-22

Exactly, it ain't worth the paper the money you paid for it was printed on

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Light, Accurate,Versatile M&P

I still think the cause of the jams is insufficient lubrication of the BCG.

This indicates to me that the OP ran the Sport on the dry side.

One big thing people miss is initial prep before shooting-

Did you strip and degrease/ clean the rifle before shooting it? Rifles come in a variety of conditions, from packed in grease, to lubed to death, to dry as a sand box, to just right.

Disassemble the bolt assembly, lube the bolt with 2 drops on the wear surface, and 2 drops on the gas rings themselves. Lube the cam pin with a drop or 2 of oil. Oil the glide surfaces, they are the flat slides on the bottom, and top of the front end of the bolt carrier. Oil the charging handle, a drop or 2 will do.
You really will not need more than this. You oil it in this manner, with the oil of your choice. Mobil 1 is good, I use Tetra and Slip, and sometimes RemOil. No heavy oils, no greases of any kind..... too sticky. Catches too much debris and slows down the action.
Dragon and JaPes are pretty spot on with their point on this. ( I DO stress staggering the rings, but the truth is.... if the rifle works reasonably well, the ring position will not detract from performance. On a really finicky, home-brew gun, it can make a difference.

In the end, lube it and shoot it silly. It needs to break in. Good luck! Paul.

Yeah Dragon LMFAO you should have posted this....




Now That is more like it children!!!!!!

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CLEAR!

I agree with Dragon, it's a waste of time trying to stagger the gas rings, where the gaps are doesn't matter. Heck, in a properly functioning AR you can get by with just one gas ring in an emergency.

And I agree you don't put oil in your magazines. The GI mags have a dry lube coating inside and the PMAGs are slick enough as is. Lube the BCG liberally not the mags.

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US Army 1966-69, VFW Member

I just read and learned a lot, time for me to clean my bcg and start over with some royal purple in a little one drop at a time bottle. Thanks guys

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Grover Oathkeeper

Ya, I read that whole instruction last night, lots of stuff in there I haven't heard of.

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Light, Accurate,Versatile M&P

I took the M&P15 Sport shooting again yesterday. All shots were from a concrete benchrest covered with a padded blanket and shooting from sandbags and rest. All ammo was Remington UMC 55 gr factory cartridges purchased from Walmart. The bolt was liberally sprayed with Breakfree CLP and the inside of the receiver was liberally wiped with the CLP. Here is my firing procedure. I place a live round in the chamber and close the action by depressing the bolt catch, the bolt "slams home" (safety on). No one else is at the range- I had it to myself yesterday. Next, I load 3-5 rounds in one of the pmags or bushmaster mags that came with the rifle. Then pushing the safety off, the rifle fires perfecly, and a new round usually cycles perfectly from the magazine as the case is ejected. This works about 90% of the time. The other 10% of the time the spent case ejects but a new round does not go completely into the chamber. I will have to then vigorously pull back on the charging handle, often tapping the other side of the charging handle with a no-mar hammer or the end of a gunsmith screwdrive, to remove the cartridge. However if I modify the loading procedure, the gun jams almost every time. Here is how it almost always jams: if I lock the charge handle back, put 3-5 rounds in a magazine, NOT place a round in the chamber, insert the loaded magazine in the lower receiver, then release the bolt catch, the bolt then goes forward, catches the live found from the magazine, and then the jam occurs, almost everytime. I then have to clear the jam by first removing the magazine. Next the jam will have to be cleared by vigorously pulling/jerking on the charging handle, and often having to rap the other side of the charging handle with the no-mar hammer or the end of gunsmith screwdriver to free up the bolt and remove the live round. This live round never gets into the chamber. The case of the removed live round will usually get dented. I have only used the Remington ammo since I cannot find anything else except Tula, and I have serious doubts about that ammo.

I did look for problems with the gas system but that appears fine. Thanks in advance for tips.

Someone put too heavy a buffer in it?

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Rod
M&P 22A, 40c, 15A, 15-22

At this point, I'd call S&W and send it in for warranty diagnostic and repair.

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-John

One quick observation....this is the second person this week with a posting using Remington Ammo? Different Rifles, different situations...Same Remington Ammo....It is not available where I am at and I have never used it BUT it is coincidental!!!

Also I am getting under an inch @ 200 and large cloverleafs @ 100 and ragged one holes @ 50...using federal xm193 5.56x45 YMMV

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Grover Oathkeeper

I don't want to cause a argument but here is the reply from smith and wesson.


"The optimum configuration is for non-alignment as the gas is forced in one direction creating greater pressure and velocity.



Aligned the gas will have less pressure and velocity as it will take the path of least resistance.





Have Good Day



Michael"

This note is a follow-up to my original post about jamming problems with my new Sport. After several more tries following ideas here regarding ammo, cleaning and oiling, my Sport continued to jam. It would not strip a round from a magazine (tried 8 different brands) and insert it into the chamber. To get this gun to fire I first placed a round in the chamber by hand, then released the bolt stop. Then I inserted the loaded magazine. Next, I would fire the round in the chamber. Given these above steps the rifle would then strip a round from the magazine and then into the chamber about about 75% of the time. However, this above procedure is not advised in the owners manual. The method advised in the owners manual is to first pull back the charging handle, push in the bolt stop, then insert the loaded magazine, then release the bolt stop allowing the bolt to move forward stripping the top round from the magazine and inserting it into the chamber. When I follow this method in the manual my gun would jam almost every time with any brand ammo and with any magazine. I also had this gun discharge (only one time) when the gun was "on safe", when I inserted a cartridge into the chamber and then released the bolt stop, thus allowing the bolt to slam forward. This gun has been sent back to S&W for repair. I am not a happy camper. I expected better quality control.

Please keep us up to date on this

did you buy this gun new or was it used ?

the fact that this gun discharged when it went into battery WITH the safety on is scary

please let us know what Smith Says?

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Grover Oathkeeper

I will keep you posted. It was purchased new in the box from Gander Mountain in Roanoke, VA on Feb 6, 2012. Gander personnel were very helpful. I called them about the rifle and its problems. Following their instructions, I took the rifle to the store with a letter of explanation of the problems. Gander is taking care of sending it to Smith and Wesson at no shipping cost to me. It is part of their in store guarantee. I sure wish the rifle worked. I have been able to get 5 shot 1.5 inch groups at 100 yds with Remington UMC Walmart purchased and Winchester white box ammo almost shooting it single shot. I want the gun to run correctly before spending money on really good ammo or working up loads. I immensely appreciate all of your ideas, questions, and suggestions. You have been most helpful and I thank you all.

I'm using 55 grain American Eagle ammo in my new (Oct.'11) M&P 15 Sport. This problem occurs with the factory mag as well as the 5 new P-Mags I bought for it. Usually about half way through a full mag it will go click instead of bang. The bolt is not fully forward, but the cartridge is in the chamber. Sometimes it is almost impossible to get the round out. I've bent 6-8 rounds right behind the shoulder in the case (as shown in picture). The rounds that do fire OK don't show any bends to them. The bad ones are really bent, not just dented. I've shot 250-300 rounds thru it so far. Is it me or does it need to go back to S&W. I've shot it 3 times and have cleaned and lubed it each time after use (appx 100 rounds each time). Any help would be appreciated. Thanks.
Tommy

Is it ejecting the spent case and still bending the rounds or is it not ejecting and the rounds are hitting the fired case. If it is the latter I would say the ejector isnt working right. If it is the former then I would question the feed ramp. Or it could definitely be a magazine issue with the mag not being fully seated. Please keep us informed of whatever you do come up with. There are some really great minds in this forum.

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Grover Oathkeeper

The previous round is ejecting fine. It attempts to feed the next round and it makes it into the chamber ALMOST all the way, but not completely. 2 of the six in the picture actually have light primer strikes on them, the other 4 the firing pin did'nt hit them. I'm thinking feed ramp problem too, as I've used 6 different mags and the problem occured with 5 of the 6 of them. If I shoot it enough the last mag will probably join the crowd too. The bent rounds are hard to get out of the chamber, but so far I have been able to get them all out by pulling on the charging handle.

The immediate post above well explains one of the problems I experienced and I started this thread. I tried 8 magazines as explained in an earlier post. Many of my cartridges looked exactly like those in the above picture. Sometimes the cartridge would not look like those in the picture, but the cartridge would not completely enter the chamber and the gun goes click and not bang. It is not an extractor problem. My rifle has been sent back to the factory with a long letter of explanation and I will keep everyone posted as to the outcome. Obviously, my rifle's problem are shared by some of you. Thanks again for all the help.

Earlier I posted problems I had with my new Sport jamming up and not firing. Those details are in my earlier posts and many of you offered suggestions. After many attempts to correct the problems, I decided to send the rifle back to S&W to be repaired. I promised you a follow-up as soon as I got the rifle back from Smith and Wesson.

I took the gun to Gander Mountain in Roanoke, VA on April 13, 2012. I attached a letter detailing the problems I had experienced with the rifle jamming. I had the rifle in the original box. I provided a copy of my letter to Gander Mountain. Gander handled the shipment of the rifle to Smith. The shipping did not cost me anything nor did I have to provide a suitable box for shipment. The original Smith box the rifle came in is not suitable for shipping the rifle, in my opinion. On May 3, 2012, I received a telephone call from Gander stating the rifle had been repaired and was received back in the Gander store that day, May 3. I picked up the rifle on May 4. There was no charge for shipping or any other cost to me. This is part of Gander's warranty program and I commend Gander on their service. I could not have asked for better service and the turnaround time from Smith was great.

I took the rifle shooting yesterday, May 7. It ran perfectly in my Pmag and 3 Bushmaster 30 round magazines. The gun ran perfectly with no jams, FTF, or FTE problems. It ran Remington factory ammo and also ran my reloads that I had full length sized. After finding the rifle firing properly, I shot the rifle off a bench rest. My five shot groups averaged about 1 1/4". This was using my reloads of LC brass, 26.0 gr of Varget, Rem primers and Hornady 53 gr HP match bullets. My scope is a Nikon 3x9, 40 mm. This has been my best load for my Sako Vixen .223 rifle also.

All in all, I am glad I returned the rifle to Smith. They fixed it and the turnaround was only about 3 weeks including shipping both ways. Gander Mountain was most helpful also. I certainly plan to keep the rifle. I very much appreciate all the helpful suggestions the readers made. The best suggestion was to send the gun back to Smith. I urge readers that are experiencing problems similar to my rifle to take advanage of S&W's lifetime warranty on the rifle and send it back for repairs.

Did they say what was wrong or what they repaired?