New M&P AR problem

[Leatherhead]

I am both new to the site and to the AR family. Here it goes I have a brand new M&P AR 15 chambered in .556 when I fire, it will fire the first round eject the spent case and chamber a new round but I have no trigger. The bolt is full forward I have to rerack and it ejects the unspent chambered round, chambers a new round and will fire one time and again I must again rerack. The weapon was cleaned and oiled before the first round was chambered. Any help would be appeciated.

 

[PPCSHOOTER]

SHORT STROKING , THE BOLT ISN'T COMING FAR BACK ENOUGH TO COCK THE HAMMER WHEN FIRED. WHEN YOU MANUALLY CYCLE TO BOLT THE HAMMER GETS COCKED. SOUND LIKE AN AMMO PROBLEM. WHAT KIND OF AMMO? JP

 

[Leatherhead]

Thanks for the help. I have been tried Winchester 55 grain, American eagle 55 grain and remington 55 grain. I am not sure if it's the same when firing but when unloaded if I pull the t handle back a quarter of the travel distance it resets the trigger.

 

[WR Moore]

OK, if the bolt/carrier group is going back far enough to eject & feed a new round, the hammer should be cocked. You can verify this by loading one round in the magazine, operating the bolt and firing this round. If the bolt locks back, it's running sufficiently far to cock the hammer.

This may be an issue with the trigger disconnector/trigger return spring. Are you holding the trigger fully back after the shot fires? If so (and you should be), when you allow the trigger to go forward, do you hear/feel a click as the trigger resets? If not, will a slight forward pressure on the trigger allow reset? If additional forward pressure is required, you need to contact the S&W Customer Service folks.

Not to be insulting, but did you read, and follow, the instructions in the owners manual for the weapon?

 

[Mack]

Lube it up, AR's run best wet and put a few rounds through it, likely still stiff from being new.

 

[BillyMagg]

I am both new to the site and to the AR family. Here it goes I have a brand new M&P AR 15 chambered in .556 when I fire, it will fire the first round eject the spent case and chamber a new round but I have no trigger. The bolt is full forward I have to rerack and it ejects the unspent chambered round, chambers a new round and will fire one time and again I must again rerack. The weapon was cleaned and oiled before the first round was chambered. Any help would be appeciated.

What Mack said, get your lube and give her a bath, what you want is to get any production particulates out of there and a good synthetic lube on the bolt and equiqment up front where it locks the bolt into the breech, I doubt your going fully into battery and not tripping the trigger disconnector,, use the forward assist, thats why its on there. If that doesn't work, then a complete disassembly and clean and lube will more than likely cure her.
If all the above fails, send her home to MOMMA, in Springfield, Mass.Uncle Billy

 

[WR Moore]

What Mack said, get your lube and give her a bath,........... I doubt your going fully into battery and not tripping the trigger disconnector,, use the forward assist, thats why its on there. :

You want a reasonable amount of lube on those parts of the carrier group that contact the receiver and the cam pin. Slathering lube where it isn't needed solves nothing and can cause more problems.

The forward assist is for battlefield expedients (and making sure the carrier group is fully in battery if trying to charge/clear the weapon quietly.) and should be used sparingly and with gentle thumb pressure. If the carrier group isn't going fully into battery during the normal firing cycle, there's something else at play. Pounding a round into the chamber isn't the answer. BTW, for the carrier group to be far enough out of battery to prevent firing, the carrier could be at least 3/16 inch out of battery and visibly not fully forward.

If you do send it back to the factory (they did test fire it prior to shipment), include a list of the brands of ammo, the makers inventory number and the lot numbers.

 

[Leatherhead]

Thanks again. I will strip it down, clean and lube up with synthetic lube this time and hit the range to see if that solves the problem. I will let you know after I do.

 

[rmw66]

It really sounds like your secondary sear/disconnector is not fitted right .
The next time you shoot it first load 1 round then remove the mag and shoot it to be safe. If the hammer is following it is poss to get a burst and of the gun goes off before it is fully locked up you will have a problem

 

[AR_Black]

Check the gas rings. Does the M&P bolt use the three gas rings? If so, make sure the cut in each gas ring does not line up with each other. I recommend the McFarland 1-piece gas ring, a great improvement over the original design.

Google ar-15 gas ring alignment

 

[Jswiney9]

Check the gas rings. Does the M&P bolt use the three gas rings? If so, make sure the cut in each gas ring does not line up with each other. I recommend the McFarland 1-piece gas ring, a great improvement over the original design.

Google ar-15 gas ring alignment

gas rings do not need to be staggered, thats a military myth that was taught to our soldiers for some unknown reason. lots of research out there on this topic.

Anyway, it sounds like a weak trigger return spring. you can order a 5.99 replacement from wolff or just send it back to the mothership.

 

[Leatherhead]

Thanks for the replies. While cleaning and lubing i found a small bur that was not letting the trigger fully return a small touch up with the file and reassembled. Hit the range this morning ( in the snow ) and she fires nice and smooth.

 

[Jswiney9]

Glad you got it figured out, now have some fun with it!