Building a 14.5 mid-length and just purchased a DD adjustable stock:

The stock description says "•For Mil-Spec receiver extension tubes".

Will the following from BCM and Brownells do the job.  The description does not state if it is for a 6-pos. receiver extension.  These have 6 hole for adjustment:

http://www.bravocompanyusa.com/Milspec-Receiver-Extension-Buffer-Tube-p/bcm%20milspec%20receiver%20extension.htm

http://www.brownells.com/rifle-parts/stock-forend-parts/buffer-tube-parts/buffer-tubes/mil-spec-receiver-extension-tube-prod27154.aspx

Do I want a H2 buffer or lighter like the ST-H?

I have also read about the "blue" spring from SpringCo.

So...obviously confused

any tube that says mil spec will work for that stock, not a tube that says commercial and my 14.5  middy runs great on a standard carbine buffer, try that first

^^ This.  Start with the standard carbine buffer and spring (unless you just like spending money  )...  

 

ETA:  Found one at BCM.  Use the standard carbine spring with this buffer?

Which of these parts comes with the little detent pin (I think that's what it is called) that holds the buffer and spring in the extension?

Those will work fine. You just need a mil spec buffer tube, not commercial. I like the ones that have an anti tilt/rotation feature like this one from POF. 6 position will work, you will have more adjustment.



http://www.pof-usa.com/shop/index.php?id_product=8&controller=product



I run a standard action carbine buffer spring and an H2 buffer in my 14.5 middy and it runs like a champ. Make sure you use good ammo in it for the first few hundred rounds or so.

Those come in your LPK.



 

The H2 is a heavier buffer?  Does it come with the little detent pin to hold it in the extension tube?

Ok...what is that part called.  I am not sure I will need a complete lpk.

Yeah, H2 is heavier. It runs really smooth with this set up. It was picky on ammo at first, I needed to run good stuff like xm193 or 855 at first, or use a carbine buffer. It runs anything now that it is broken in, I was shooting steel case wolf out of it with no problems last week. The detent and spring come in your lower parts kit.

ETA: Buffer detent and buffer detent spring. PSA has a good selection of individual pieces as well as other places. Try to place your orders from one vendor if possible to cut down on shipping charges. Check out the battle arms development enhanced take down pins for ease of installation of the pivot pin. The use of a magnet with these pins is genius.





 

Well...I am looking at buffers and extension tubes from BCM and some made by LMT.

Which to go with??  Better quality?

Can't go wrong with either. LaRue has a nice one as well. I'd go with the POF one but that is just me, I really like the anti rotation.



 

It's the buffer retention pin (needs the spring also)...

 

I run H2's with my 14.5" middy's but that doesn't mean that it will work for you. Start with a carbine buffer and go from there. Once you break the rifle in, then decide if it needs a heavier buffer. If you feel that it does, get an H2. If the H2 is too heavy, you can swap one of the steel weights from the carbine buffer with a tungsten weight from the H2. Essentially making a H buffer.

Carbine buffer has 3 steel weights
H buffer has 2 steel and 1 tungsten weight
H2 buffer has 1 steel and 2 tungsten weights


The BCM tubes are excellent as well as their buffers. Also use a standard mil-spec carbine action spring. The only time I have run into cycling issues was when using fancy NASCAR springs. Buy a half dozen or so and you'll be good to go for quite some time.

I'm not sure what the ST-H is but if it's like the ST-T2, it won't do anything better than a H or H2.

Vltor A5 should be in every rifle.

Tried it. It didn't blow me away or anything.