9mm build questions

[WWGunslinger]

I am in the process of building an 9mm AR. I want to eventually SBR it, but while I wait for that, I think I want to make it into a pistol to play with it first.

Regarding the buffer tube, assuming I do pistol now and SBR later, do I need 2 different buffer tubes or will 1 buffer tube work for both?

I'm also kind of confused what buffer to use. I see posts online about using a 9mm specific buffer, using a regular AR 15 buffer, using spacers, etc. What exactly do I need here?

[BB MBD]

For pistol you need a pistol buffer tube. The one that not gonna allow an immediate stock installation. I've seen someone wrapping paracord around regular carbine tube preventing stock installation but I would stay safe and use pistol tube.

As of buffer. It needs to be specific 9mm buffer. I use this one without any spacers
http://www.jsesurplus.com/yhm9mmbufferplugassembly.aspx

Also if you make it out of multi caliber lower you need a mag adapter.
And obviously 9mm bcg.

[USMC3531]

i use a regular h3buffer and a homemade spacer so the bolt doesnt travel too far.

[Seabee CO]

I pulled the buffer out of my Colt SBR and took a picture for you if it helps. Started life as a 6450 then I replaced the Colt 16.1" upper with a Colt SMG upper. The lower is original Colt.

IMG_0531.jpg

Good luck.

[Emptymag]

Here's my 9mm (carbine) build thread. I had a lot of questions about 9mm ARs and got a lot of good info.

The 9mm buffers are a specific weight that differs a bit from "normal" buffers.
The "9mm buffer spacer" goes on the other end of the buffer spring.

Like in this pic I found online...



The buffer tubes themselves are (as already mentioned) different - a pistol buffer is made so it can not accept a stock.


On my 5.56 pistol, I used the KAK Shockwave Blade and have no regrets. Way less money than a Sig brace and not as clunky looking.

[Emptymag]

For a 9mm AR15 the 9mm specific parts are:

9mm barrel (no gas block or gas tube needed - it's blowback)
9mm Bolt Carrier Group
9mm Buffer
9mm Buffer spacer

9mm dedicated lower (magwell sized to accept one of two options - Colt SMG mags or Glock mags)
OR
Standard multi-caliber lower with 9mm mag block adapter

Each have their pros and cons.
Dedicated 9mm lowers are usually less costly. Mag blocks for standard lowers can get pricey for good ones.
Mag blocks are removable should you ever change your mind and want to use the lower for another caliber.
Glock or Colt pattern mags? Individual choice - I hate the appearance of the angled Glock mag and prefer the classic look of a Colt stick mag.

Have fun. I wish I had built my 9mm as a pistol instead of a carbine, but I will remedy that one day by just building a new pistol in 9mm!

[39flathead]

I'll just leave this here:

[BB MBD]

I'll just leave this here:

Oh I got so much to say about company/receiver/ffl chain operation but that will hi jack this post.

[WWGunslinger]

I ordered a 9mm specific pistol buffer kit that comes with tube, buffer, castle nut, plate, and spring.
Do i still need a spacer for a pistol buffer tube?

Next question - I am killing myself trying to decide on what upper to go with. It looks like some people use regular .223/5.56 ar15 uppers?
If I can use a regular .223/5.56, is there any downside to this vs using a dedicated 9mm upper?

Thinking about building my own upper as I doubt the one I want from PSA is going to be in stock any time soon.
I thought about side charging 9mm uppers but they are like double the price of regular 9mm uppers, and some people seem to have issues with them while others have no issues.

[Emptymag]

No difference I'm aware of.

Double check, but I don't think 9mm BCGs have serrations for a forward assist. I'm not 100% sure in that though.
I bought a slick side upper with no FA and no dust cover.

Oh! That's probably the difference on a dedicated 9mm upper - they will have the half door dust cover and that "bumper" thing.
I have no issue shooting mine without one of those and was told it wasn't necessary.

Tomstactical.com had Aero slick sides WITH a dust cover for a really good price.