M&P 15 Sport ejection issue

[Mucciman]

Hi I have a M7) 15 sport 5.56. It is one of the older ones where the upper has the A frame front site post. I recently replaced the upper to get rid of the front site post with a 10 inch upper, Now I am have a problem with the casing ejecting.

I am sure this is a gas issue and its under gassed, just not sure how to fix it. any thoughts?

Thanks

 

[Yendor357]

I don’t know what an M7) is. I googled it. No luck.

If you put a 10 inch barrel on a rifle, that is a felony.

From what I gather, getting a 10 inch gun to work requires some know-how that I do not posess. You’d probably need a different buffer, among other things.

Do yourself a favor and put your gun back together the way it was.

 

[hardluk1]

IS your M&P15 a pistol or sbr legal . You can not change a carbine to a handgun or sbr . Remove your upper and order a AR15 pistol lower . Go to PSA and find a AR15 pistol lower for as little as 120 bucks tp 220 . I run a 10.5" ar15 pistol and run with a TUBB flat wire buffer spring in our AR15 carbine our 9mm or 5.56 pistol .

The 5.56 10.5" barrel pistol does seem to like the 5.7oz buffer weight with the tubb spring and runs reliably throwing brass to 3:30 to 4:00 poisition with both 223 and 5.56 ammo .