Hi all,

Looking to start my first build on the AR platform. I'm struggling to decide what to build so I wanted to hear some opinions!

A little Background:

I currently own:
S&W Bodyguard
Sig P320 X compact
Tikka T3 Lite
Remington 870
Mossberg Shockwave
PSA 16" AR15 - .556

I recently picked up a stripped lower and I'm trying to decide if I should build an AR pistol or more long-range AR.

To go ahead and put this out there - I know your gun should "match your mission". I'm struggling to decide which mission to pursue first.
While I have the shockwave for my wife to use for home defense, I've been planning to use my 320 as my weapon of choice.
If I were to build an AR pistol, I'd switch over to using that.

So, I lean towards building the AR pistol.

For the builders out there, where would you start? (This will be my first build.)


If I go the pistol route, it then brings up the choice between 556 and 300 Blackout. I'm sure that's a much longer discussion with many varying opinions. I lean towards 556 just so I don't have to worry about a buddy accidentally loading a 300 round in my other AR 556 barrel.

I built both 5.56 and 300 pistols recently.  The one thing that is problematic about 300 right now is availability and cost of ammo.  It is hard to find and the few places I can find it they mostly want $2+ per round.  In my experience a 300 round usually won't chamber far enough into a 5.56 to be really bad, it is the other way around that is a bigger issue.  A 5.56 round will go all the way into a 300 chamber.

One thing I've done is my 300 pistol is all FDE and the charging handle has "300 BLACKOUT" printed on it, and the mags I'm using with it and my 300 BO rifles are all FDE also.  The color coding is something I've done before with other rounds that could get confused.  For the ammo I use in my Gewehr 1888 Comission Rifle for example I actually mark the head of the brass with a blue Sharpie.  Only that blue marked ammo goes in that gun because it is loaded with a .318" bullet instead of the .323" all my other 8x57 Mauser rifles use.

Please don't take offense, but probably the worst possible option for her, IMHO.  Build her an AR-9 using Endomags so you can use your standard lower.

Since you already have a 16" I'd build either a shorty or a longer barrel precision rifle. If you go with a shortie you have 556, 300 Blackout, 9mm, etc... to choose from.

A 308 or another common variant wouldn't be a bad idea. I had a short, 16" and a long AR and then built a really nice 18" 308.

Honestly ... good luck finding anything in stock though. You might have to shell out top dollar for stuff that is in stock and/or sacrifice by buying stuff you ordinarily wouldn't just because it is in stock.

Honestly, I'm glad you said that cause I've been thinking about it for a while debating if I liked the idea of her using it or not. Appreciate the comment!

I'd go for a 9mm carbine using Endomags.

Aim Surplus just had a complete FM upper w/ side charging (rocks!) for $400 (about $10 more than this time last year)

If you are looking for a LPK check for Joe Bob Outfitters and the "Enhanced LPK w/o Grip".  Awesome ambi safety (60/90 throw, scalloped short off side) and the trigger is better than the PSA EPT offering.  Add a couple of Endomag inserts and you'll hit the free shipping too.

Thank you very much sir!!

You already have the lower, so forget a.308.  was the lower purchased as a rifle? If so you can't use it for a pistol.. probably build whatever ammo you can get.