Convert a M&P15T to SBR?


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ChrisMG
January 3, 2012, 10:14 AM
I'm in the planning stages for an SBR & suppressor (11.5" barrel) on my M&P15T. Questions I have though, what do I need besides the barrel? If I purchase a BCM "stripped" barrel, what do I need to do in regards to the gas system; can I just use the stock parts off the M&P?

I'm mostly concerned with how the gas system works with the stripped barrel and it being shorter than 16". Since my M&P doesn't have a front sight block I'm guessing it has one underneath the hand guards (not sure if it is low profile or not).

Going SBR, would it be advisable to look at an adjustable gas block?

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Dustin0
January 3, 2012, 02:13 PM
11.5 sbr uses carbine gas system. I dont think you should have any problems

MasterSergeantA
January 3, 2012, 03:23 PM
So long as the diameter of the new barrel is the same as the current one, there should not be an issue. As Dustin pointed out, the rifle uses a carbine gas system and should work with the shorter barrel.

I don't have a sample of the rifle to examine, but based on the stock photos, it appears to have a low profile or similar gas block. It doesn't look like one of the railed blocks would fit the small space and that might create an issue with the adjustable gas block unless you shortened the forend. You probably don't need it with the suppressor, but some folks on here that have used them might offer more comprehensive advice.

4thPointOfContact
January 3, 2012, 03:42 PM
15T - low profile gas block; secured by set screws, 7.5 inches.
Stock free-float handguards are 10" long from the face of the bolt and shouldn't need changing unless you don't mind throwing out a few hundred dollars of aluminium.

As I also have daydreams of SBR'ing my 15T, I plan on keeping the stock FF rails, and sights. The only thing I really see being needed is a barrel with the proper diameter hole, a gas tube and another low-profile gas block to make it an easy swap.

bit_bucket
January 20, 2012, 01:07 AM
Be sure to post info about your conversion. I also have an M&P15T and was thinking of switching to a short barrel but without the suppressor.

Thanks very much.

-Bit

rjrivero
January 20, 2012, 01:51 PM
Sorry. Double tap.

rjrivero
January 20, 2012, 01:54 PM
You can have your current barrel cut down crowned and threaded when the Form 1 comes back. They'll check the gas port to be sure it's in spec for the given barrel length. Adco charges $65 for cutting, threading, crowning. Adjustable gas blocks are not necessary. I have a 7.5" upper, and a 11" upper both run fine without adjustable gas blocks.

www.adcofirearms.com (http://www.adcofirearms.com/shopservices/shop_.cfm?code=1)

What kind of handguard are you running? You should be able to see the gas block under the handguard. Any chance you could post a picture?

dprice3844444
January 20, 2012, 03:02 PM
you doing a barrel over suppressor to fit under handguards? if so,you will have to hunt for the handguards with the largest internal diameter.if you can get longer than carbine hg to use,go with them.less chance of burns.

make it to where after the first chamber is behind the threads and you use a nut/lockwasher to secure it on the 1/2 x 28 threaded flash hider threads,baffle out from there,you might get away with 1 tax stamp

now,as with the mac cans using rivets/wire cloth.check with local old type hardware store and see if they have any stainless screening.check online sieve manufactures for same.

http://search.aol.com/aol/search?query=fine+stainless+cloth&s_it=keyword_rollover

dprice3844444
January 20, 2012, 05:34 PM
or,if your just going to do a short barrel with a crew on can,check the mfg's for a barrel heat sink.one of the makers had one for one of their compatition guns

http://www.amazon.com/How-Build-Military-Grade-Suppressors/dp/0879471956

http://www.xdtalk.com/forums/ar-talk/145284-suppressing-ar-worth.html

http://www.weaponoutfitters.com/products/ar-gas-vent

http://www.ar15.com/mobile/topic.html?b=7&f=118&t=870401&page=1

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