MP 10 buffer guestion

[Armed62]

My BA is getting hammered.

is this normal?

Edited June 5, 2021 by Armed62

[Lonewolf McQuade]

Round count?

[jtallen83]

11 minutes ago, Armed62 said:

is this normal?

No, looks like your buffer is hitting the buffer detent instead of coming to rest on the carrier. The only time the buffer should be in contact with the detent is when the upper is opened up. Check to see if you carrier pushes the buffer off the detent just as the upper closes. If not an offset buffer retainer may be in order. 

https://gallowayprecision.com/offset-buffer-retainer-for-AR-15-rifles

 

[98Z5V]

^^^   All true, right there.  But, is the receiver extension screwed in all the way, or can it go in one more turn?  What's the internal depth of the receiver extension?  What's the buffer length?  Pending the answers to those questions, it might be out-of-spec parts, or it might be as easy as screwing that receiver extension in one more turn.

Pics help.  Greatly. 

[Armed62]

Great guestions,

Im in pieces now waiting for a handguard.also recently added a wilson combat upper side charger and i had to rat tail a little material out of the pin holes to mate the S&W lower. With these questions leads me to believe the upper is 3 or 4 thousands to far forward from the buffer tube. BTW the tube in screwed all the way forward. I will come back with some pic’s when shes back together. Thanks for the help, though ill need you guys a little more.🤠

[mtrmn]

Read this thread for more solutions to this problem:

ETA: screwing the buffer tube in more will not fix this. The hole for the buffer retainer would have to be re-located or the aforementioned offset retainer installed.

Edited June 5, 2021 by mtrmn

[Armed62]

Mtrmn, i would have never though of this. I have access to the tools needed. Thanks so much.

[mtrmn]

You're welcome. Pretty sure you are right and your problem was self-inflicted by mis-matching lowers and uppers. There are no standards between brands of the large frame ARs and by forcing the fit with a file you probably did move the upper too far forward. My remedy will allow it to work, and you can still use the same buffer next time you swap uppers. Maybe I should have patented this...🤔

[Armed62]

🤠 yes You should patent it and thanks very much for the advice

[shooterrex]

Before you start drilling on things how about you put a few layers of duct tape on the face of the buffer and see it that solves the problem. If that works then you will know  modifying the buffer tube is worth it.

[mtrmn]

21 minutes ago, shooterrex said:

Before you start drilling on things how about you put a few layers of duct tape on the face of the buffer and see it that solves the problem. If that works then you will know  modifying the buffer tube is worth it.

This is a good idea to be on the safe side. Tape on the face of the buffer to see if that's enough to make contact with the bolt carrier and push the buffer away from the retainer. Then you can measure the tape thickness to see how much you need to cut to break contact with the retainer.

However, if you do cut the buffer unnecessarily it won't effect the gun's operation. I can use the cut down buffers in any AR15 I have, even those that don't need that modification, without any adverse effects.

[Armed62]

That sounds like a plan. Still waiting for a guard from phoenixweaponry. Dont like the rifle in 20 pieces.🧐 Which is why you should never have just one lol

[mtrmn]

Just need to add this: Make sure there's no tape between the buffer and the retainer. The retainer must contact the buffer and not the tape for this experiment/measurement to work.

Edited June 6, 2021 by mtrmn
added info

[Armed62]

I found a off set retainer in the great white north. Works well, ten rounds and no contact. Thanks for the help🤠

[mtrmn]

👍👍