Just got a new Sport II, but had a failure to extract after only about 50 rounds.

The next round jammed up against it. No way to get it out, needed a cleaning rod to clear the malfunction. Feeling pretty sour about it, have many rifles and never had this serious of a malfunction.

Should I send it back to the factory? Or is this normal for ARs? This is my first AR.

More than likely there is nothing wrong with the AR it is the magazine-every time I have witnessed a double feed such as this it was the magazine lips getting weak.
This is especially true in Magpul and such with the polymer feed lips.

Pull the bolt out of the carrier group and check the extractor claw. If it looks undamaged, remove the extractor and check this part of it.

How AR-15 Extractors Break - YouTube

I'll have a look at the bolt and extractor. Thanks for the video link.

Appreciate your reply. It happened with the factory metal magazine (I have the 10 round state compliant one). And it wasn't wasn't a double feed - the fired round did not extract, and then the next round got pushed on top of it.

Factory ammo or reloads?

An improperly sized case would stick in the chamber.

.

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Waiting for the break of day

Factory Tula ammo. The stuck case did have part of the rim broken off, but not sure if that happened before or after was trying to clear it out.

I the rifle properly lubricated? The wetter the better.
Also rifles that dont have true5.56 chambers suffer failure to extract with steel cased ammo.

Yesterday I did completely disassemble the bolt and the extractor looks intact. So will assume it was a fluke for now, and try again.

Classic stuck steel case. Is you rifle dry? a dry rifle is a bad rifle. Run a chamber brush, lube the rifle. THE WETTER THE BETTER, as said by Pat Rogers.

If you can, remove the bolt and remove the extractor. Is there an O-ring under the extractor and around the extractor spring? That O-ring helps the extractor get a better grip on the rim of stubborn cases in the chamber.

BROWNELLS AR-15 EXTRACTOR SPRING O-RING | Brownells

Also if you have been firing Wolf or other steel cased ammo, make sure you use a regular chamber cleaning brush on a regular basis. While the steel cased stuff works fine in some of my rifles, it is universally dirtier than brass cased ammo and the chambers get dirty quicker, making the cases a little more reluctant to extract.

It looked pretty wet... but I re-lubed yesterday to make sure. The barrel on mine is marked 5.56 NATO, hopefully the chamber is sized right, but maybe the cheap Tula ammo is not consistent.

That "keep it wet thing" is one the internet experts love, because they don't have to really know anything. It doesn't have to be dripping to be properly lubricated. I believe you've already located the real source of your problem:

"...Tula ammo. The stuck case did have part of the rim broken off..."

A true 5.56 chamber will run cheap Wolf, Tula steel cased ammo perfectly.
In fact Wolf/Tula is a great barometer to judge if you rifle is battle ready.
I suspect you don't have a true 5.56 chamber.

Yep, o-ring was there. This was my first 80 rounds out of a new rifle. I'll get a chamber brush - thanks for the advice.

Do you have chrome lined bore and barrel?

Don't get distracted. Your problem is not a extractor issue. It is a chamber issue.

I have this: M&P 15 Sport II | Smith & Wesson
Armornite (hardened nitrite) finish on interior & exterior of barrel. The barrel is stamped 5.56 NATO as I said.

I'm thinking the problem may have been a brittle case rim as Bullet Bob suggested.

Or maybe too much factory lube in the chamber? I didn't swab it out like I should have before shooting.

That's not a lube, it's a preservative to prevent rust. The rifle should be torn down and cleaned before it's ever fired.

That’s an ammunition related issue.

Tula steel cases don’t expand like brass so they don’t obturate (seal) the chamber allowing the blowback from their filthy burning power to gum things up, forcing the extractor to work harder.

Sometimes it so difficult to extract the steel case that a piece of the rim breaks off resulting in exactly the same type of stoppage you’ve experienced.

Keeping your rifle clean and properly lubed will ameliorate the problem.

After firing steel cased ammunition, you’ll need to take extra care in thoroughly cleaning your chamber before firing brass cased ammunition because the brass will expand tightly against the powder residue and jam up your rifle.

Im sure Pat Rogers knows more than you do.
S.W.A.T. MAGAZINE – FILTHY 14 : Slip 2000 Official Blog

Respectfully, there is the actual knowledge gained through decades of personal experience with a particular firearms platform; and then there’s the sort of knowledge which is gleaned from reading articles in Gun magazines and regurgitating them online.

So the real answer is that the Smith and Wesson MP Sport 2 has a carbine length gas system. The dwell time is too short to reliably cycle most steel cased ammunition that is uncoated as Tulammo is. There are of course exceptions to this, which someone will soon chime in with but as a general rule this is true.

Shorter dwell time means higher pressures in the case as the gun unlocks and begins to extract. This is not an issue with brass and generally not an issue with some coated steel case as the friction is low enough between the chamber wall and the casing to reliably extract. Not so with bare steel. No amount of lubrication or chamber scrubbing will fix this, the issue is in the short gas system. Your gas port sizing can also play a role in this, a larger gas port will typically have the umph to muscle the case out (or shear the rim). Smaller gas ports may not. Either way you're eventually going to shear off your extractor. I don't know what Smith and Wesson's spec on the gas port is.

The carbine length gas system was adopted to ensure reliable function in dusty and dirty environments and in rifles that may not be well maintained, but specifically for brass cased ammunition. As a result most carbine length guns are significantly over gassed to ensure function. The trade off is a short dwell time, high pressures during primary extraction, a sharp snappy recoil impulse, and guns that typically don't run steel very well or destroy extractors.

Mid-length systems have a longer dwell time, which allows the pressure to drop a bit more, and the case to contract a bit more, before the gun begins to unlock and thus typically run all steel very well. It's why mid-length gas systems are so prevalent now and rapidly becoming the norm. Additionally with a properly sized gas port they run as reliably as carbine gas length guns. They also have a much smoother and softer recoil impulse for a gun of the same weight.

Rifle length gas systems follow the trend and are typically very soft shooting and run well with most ammunition. Some rifle length gas systems actually wont cycle with Tulammo because it is rather underpowered as .223 offerings go. One of mine will not reliably cycle with it. It short strokes, not enough gas pressure to complete the cycle.

Anyway, there's your answer. If you continue to fire the rifle with steel cased ammunition you will continue to have failures to extract, damaged rims, and eventually you will shear your extractor and have to replace it. Some steel cased offerings will work better than others, you will have to try different ammunition. I have sheared the extractor on my carbine length gas gun and I have seen it many times. I sheared mine on the wolf military classic with the green lacquer. People will give you the "mine's just fine" routine, most of them haven't put a significant number of rounds through their rifles. It took me about 3500 rounds. Thankfully its a cheap and easy repair easily off set by the money saved through shooting steel.


Edit : For proper lubrication, thin layer of TW25B on the sliding and camming surfaces of the BCG and associate parts as well as on the exterior. One drop of your favorite oil through both of the carrier gas vents, and work the oil into the gas rings by articulating the bolt back and forth by hand. The fouling will wipe off with a paper towel the next time you go to clean.

Keep the FCG clean and greased and your rifle will run like a clock.

Chiming here. Every Tula round whether 5.56 or .45 ACP I've had has been polymer coated. My guns run it like grease through a goose.

To think that you believe you are more qualified than Pat Rogers is amusing.

Unless an individual has the weapon in hand along with the expertise to diagnose the problem, any solution offered is nothing more than conjecture; speculation at best. Some are decent swipes and some have discounted problems which are actually demonstrated by the OP's malfunction.

I have no problem with many of the replies. But the ones which totally toss aside one of the possible problems is without merit. Good luck OP.

Isn’t Tula ammunition actually .223?

Which is what the O.P. is tying to shoot in 5.56 chamber. Shooting brass case .223 in 5.56 chamber doesn’t cause problems because brass is soft enough metal to conform to the 5.56 chamber when it is fired. I do not think steel case will conform to the 5.56 chamber.

In other words you can get away with cheating using brass case .223 but not with steel case .223.

I shoot my steel case .223 in my Saiga .223 carbine without any problems whatsoever.

Yeah it is .223 but the cases are the same. The only difference is pressure. That's why you can't shoot 5.56 in a .223 chamber.

The pressures are actually nearly identical, too. The main difference is that SOME 5.56 loads are longer than the maximum .223 length. This is due to longer length bullets used in some 5.56 loads. In order to accomodate the longer loads the 5.56 chamber has longer free bore than does the .223 chamber. Free bore being the distance from the chamber to where the rifling begins. Those longer bullets in a .223 chamber may be jammed into the rifling upon being loaded into the chamber, and THAT could cause a pressure spike when shooting those particular loads in a .223 chamber.

Generally speaking, it is safe to shoot 5.56 in a .223 chamber IF the load being shot does not exceed the maximum length specified by SAAMI for .223 loads (1.4696 in.)

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Or something like that . . .

Simple solution. Lubricate and try brass case ammo.

I don't run steel case ammo in my AR's, as it can be finicky in some rifles.

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Watch & Pray

I had the same problem and found 100 different reasons why. Since the steel cases don’t expand to properly seal causeing the dirty power to build up I came upon a simple solution. I had bought 1,000 rounds and I’m to tight not to shoot them. So when I load my mags with steel case rounds I use a brass cased round as the first and last round. Never had a stuck round after that. Try it and pick up and look at the brass round, it will be black. I’m a simple man who likes simple solutions.

There is a slight difference in the shoulder chamber dimensions.

As for 5.56 in the .223 chamber debate I am sure we could have solved the recent energy problem in Texas.

I shoot SCA about 99% of the time in my AR's. I have installed a BCM extractor spring upgrade kit in each of the BCG's. Works like a charm.

BCM SOPMOD Bolt Upgrade/Rebuild Kit
BCM Extractor Spring Uprade Kit

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How many guns are too many?

Thanks for the education on the gas system -- I'm really interested to learn this kind of detail about the platform. I ended cleaning everything with mineral spirits and oiling/greasing pretty much as you described. Will see how it works next time I shoot.

Interesting to know, thanks. Trying to find more info on the NATO chamber, all I can find so far is that the max overall length spec on the cartridge is 2.26"/57.4mm

The difference is in the leade, the area in front of case mouth
that transitions from un-rifled, 'groove diameter' bore to
rifled bore.

The 5.56 has a longer leade, so can accept a wider ogive
slug, seated out farther than a .223 chamber.

The "possible hazard" concept comes from using 5.56
rounds in a .223 chamber, where the 5.56 slug might end up
contacting the rifling in the barrel, causing an increase in
resistance to the bullet getting started down the bore.

I found these images that show the differences on blog.westernpowders.com

Attached Images

	chamber-stuff-72.jpg (103.0 KB, 18 views)
	real-chamber-photo-72.jpg (207.6 KB, 18 views)

Good work. You may become a dentist, if you keep it up

Keep in mind that chamber cutting tools wear, and as they
do, their outer diameter decreases--resulting in a tighter
chamber.

Business is business, tooling costs, downtime to replace
tooling costs, yadda yadda, etc. Some rifles will go out with
chambers reamed a few thousands tighter, when the cutters
were approaching whatever the prescribed "barrel count"
replacement limit is (assuming guys on the line adhere to
guidelines...seeing possibility for variance? ).

Assuming there's nothing else weird going on (surface defect
in chamber that gives case something to 'grab' on), or the
stuck round had defect in metallurgy of case that allowed
rim tear-off, your rifle probably has a marginally-tighter
chamber. It might not ever like Tula, or over time it may
'work in' and get mo better. Or, you could send the upper
back to S&W, and ask if they could touch-up the chamber.