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1/15/2014 7:11:00 AM EDT
Doing a budget build for a good friend and I've never had to choose a buffer weight for this setup. I'm thinking an H1 or ST-T2, but would like to hear some first hand experience from some of you.

16" Carbine M&P15T barrel
M&P15T semi-auto BCG
BCM carbine stock mounting hardware kit (buffer tube assembly)
1/15/2014 7:33:31 AM EDT
[#1]
I'd test fire it with H and H2 buffers handy. If I had to make a guess I'd buy a H2 buffer. They ship with a carbine buffer, but I personally would never run a carbine gas system with a carbine buffer.
 



ETA they are overgassed as it is so H2 buffer
1/15/2014 8:06:51 AM EDT
[#2]
Yeah, that's what I am thinking...H2. My guy knows nothing about black rifles so I would like to get it right the first time for him. I have read that the gas-port on the M&P15T is slightly larger than mil-spec.
1/15/2014 8:10:04 AM EDT
[#3]
Always start with a carbine buffer.

After break in when everything is functioning properly, you can buy a H2 buffer if you still want, and try experimenting with (try a H1 by by swapping the weights around between the buffers).
1/15/2014 8:18:21 AM EDT
[#4]
Quote History
Quoted:
Always start with a carbine buffer.

After break in when everything is functioning properly, you can buy a H2 buffer if you still want, and try experimenting with (try a H1 by by swapping the weights around between the buffers).
View Quote


That is what I have always done with my mid-lengths (14.5" and 16"), but I am reading all over that the M&P15T has a larger gas port and tends to be overgassed with the carbine and even H1 buffer. Found 2 guys on the S&W forum that have this same M&P15T upper with H2 buffers and it ejects Wolf .223 ammo at 3 o'clock. That sounds like a winner to me, but would like to hear anyone else's experience with M&P uppers.
1/16/2014 3:20:24 PM EDT
[#5]
budget eh?
Do you have a "extra" carbine buffer? yea.... one of the cheap ones. Try this:
Remove the roll pin in buffer, remove the rubbery end cap, remove those high tec recoil weights . Fill with lead shot (I pounded 44 lead shot to size) place enough in to fill. Replace end cap.
Mine is 4.6 or 8 forgot right now. Works great

I also found some 5 oz buffer on Amazon for 9.95 (bought 2; actual  weight 4,9 oz) they worked great also.

1/17/2014 5:09:52 AM EDT
[#6]
Any change in buffer spring when going to a H2 buffer?
1/17/2014 5:14:17 AM EDT
[#7]
OP do not over think this so many people think they must have a heavy buffer or the rifle will be unreliable.  My suggestion is start with a Carbine buffer if it works it works go with it.  If you are over gassed change out for an H2/T2 buffer but honestly do not overthink it so much.
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