New S&WMP15 fail to feed/short stroking

[40S&WMAN]

This is frustrating, especially since I decided to shell out a few extra hundred bucks to get the “better” S&W over the DPMS or Olympia. I used new federal premium 50 grain jacket hollow point that has worked in my other AR’s fine, I tried three different brands of quality mags, field stripped, cleaned and lubed, no go, and I have to manually cycle the action every round. I just bought it last week and I am taking it back to my dealer to have his gunsmith look at it, I’m sure the shop or S&W will make it right, but sometimes it feels better to rant about it................................

[DefensiveCarry.com]

[SubNine]

This is frustrating, especially since I decided to shell out a few extra hundred bucks to get the “better” S&W over the DPMS or Olympia. I used new federal premium 50 grain jacket hollow point that has worked in my other AR’s fine, I tried three different brands of quality mags, field stripped, cleaned and lubed, no go, and I have to manually cycle the action every round. I just bought it last week and I am taking it back to my dealer to have his gunsmith look at it, I’m sure the shop or S&W will make it right, but sometimes it feels better to rant about it................................

Sorry to hear about your misfortune with your M&P15. I would try a different type of ammo and see if that works, if not, take it to a gunsmith. Good luck to ya, and hopefully you can get it working right.

[Skygod]

It sounds like a timing problem, since you did you have lubricated the weapon properly.

It could be anything as easy as lightening up your buffer or replacing your mag followers and springs. I'm just wondering if your gas port is to small or your gas tube is obstructed in any way ?

I'm just guessing, but guessing from experience.

[C4iGrant]

This is frustrating, especially since I decided to shell out a few extra hundred bucks to get the “better” S&W over the DPMS or Olympia. I used new federal premium 50 grain jacket hollow point that has worked in my other AR’s fine, I tried three different brands of quality mags, field stripped, cleaned and lubed, no go, and I have to manually cycle the action every round. I just bought it last week and I am taking it back to my dealer to have his gunsmith look at it, I’m sure the shop or S&W will make it right, but sometimes it feels better to rant about it................................

Check that you have an M4 barrel extension with an M4 upper receiver.

To check short stroking, load one round into the mag and fire it. Did the bolt lock back?


C4

[rocky]

That sucks , hopefully you can get it fixed quickly.

[AKsrule]

It sounds like a timing problem, since you did you have lubricated the weapon properly.
It could be anything as easy as lightening up your buffer or replacing your mag followers and springs. I'm just wondering if your gas port is to small or your gas tube is obstructed in any way ?
I'm just guessing, but guessing from experience.

Yup , short stroking almost always means not enough gas.

[40S&WMAN]

*update* i had ruled out the ammo, but it was the ammo, the shop took the rifle to the back wherer they had a test fire chamber, turns out the federal ammo i had was so weak it would not cycle th action, we tried some american eagle tactical xm193 it worked fine. what sucks is i have 1000 rounds of this federal .223 that the S&W dosent like

[AKsrule]

*update* i had ruled out the ammo, but it was the ammo, the shop took the rifle to the back wherer they had a test fire chamber, turns out the federal ammo i had was so weak it would not cycle th action, we tried some american eagle tactical xm193 it worked fine. what sucks is i have 1000 rounds of this federal .223 that the S&W dosent like

Underloaded ammo is a rare occurence , and Federal is known
for making good ammo.

I suggest you call Federal and send them a few rounds of your
ammo to test.

[Superhouse 15]

We had an issue with Federal American Eagle ammo a few months ago. Dented cases that wouldn't chamber, a few rounds from a few different boxes in a case. Federal replaced everything at no cost. Absolutely send those rounds in. They'll make it right and you might getr a recall that could help a bunch of other shooters.

[40S&WMAN]

I emailed federal, one problem is i repacked most of it into 100rd waterproof plastic cases to seal/preserve it, and i dont have the receipt...

[njeske]

I also have this issue from time to time with the Federal 50gr hollowpoint ammo cycling through my M&P15. It's not usually every round, but sometimes as many as 5 rounds in a box of 20 that won't fully cycle the action. I just have to manually pull the bolt to fully chamber the next round and then I can continue firing. I've never had this problem with any other type of .223 ammo.