Hey Everyone!
Here's my home built 12.5" Pistol and this is a breakdown of its first range trip. I was testing a bunch of defensive ammo to see what it liked and was all shot over a long lunch break before ammo dried up. ;)
My purpose for this pistol was to create a lightweight HD 5.56 that my wife could handle that would also make a good all purpose ranch gun if needed to deal with coyotes or bobcats. I went with FDE because if it ever got dragged into a court, I wanted it to be anything but black. I decided reliability was the most important factor and that balance is more important than overall weight.

I have a 10.5" that's too loud. Using my GoogleFu, it seemed that there's a significant enough jump in velocity from 11.5" to 12.5" to make me decide on a 12.5". During my parts acquisition process, I was having trouble finding a good 12.5" pencil barrel. I'm of the opinion that Gov't profile barrels are stupid for Civilian guns. All they do is add a bunch of unnecessary weight to the end of the barrel on an already front heavy platform, so I refused to encourage their manufacture by buying one. I was really hoping Faxon made a 12.5" Gunner or Pencil but in the end, I couldn't find one under 20oz. Ideally, I wanted a 1:8 twist but I've been interested in a trying a Triarc TRACK barrel for a while so I decided to give it a shot. If anyone makes a 12.5" pencil in a 1:7 or 1:8 twist let me know, I might change barrels later and use this one on another build. I noticed that there wasn't much in the way of info or reviews on Triarc's barrels other than people saying they're great or meh and making claims but no proof. I'm here to provide a sample.

The gun is built around an Aero M4E1 receiver set, a 12.5" Triarc TRACK 2.0 barrel w/ 1:7 twist, pinned Superlative Arms gas block, Sharps XPB and an ALG trigger (ACT) with a Romeo 5 red dot on top.




After I finished the build, I went researching some soft points to use and ran a bunch to see what it liked. This too is a balance but between precision and reliability. The final winner was impressive and that too, I couldn't find much info on. The difference between the Hornady Black 75gr Interlock HD SBR Soft Points (which is far too long of a name) and the next best competitor was almost double the group size. The groups below were shot off a bench using a Romeo5 with a 2 MOA dot and a 4x magnifier. The 50yd groups were a little smoother and shot first to dial in the red dot. The 100yd groups suffer from some fatigue, rushing a little to get back to work and were fired in between the shots of the guy next to me who had a wicked brake on his rifle that rang my bell a little. With some match ammo, a scope and a better shooter, I think it is mechanically a 1-MOA or sub-MOA gun. Needless to say, I was very impressed. All measurements were made using the Ballistic-X app on Android.

My best 5 shot group at 50yds.
https://www.northwestfirearms.com/attachments/20190925_210527_resized-jpg.620023/

Next best group at 50yds.
https://www.northwestfirearms.com/attachments/20190925_210511_resized-jpg.620024/

Longer 8 shot group at 50yds. Stopped before I remembered what time it was and still wanted to go to 100yds.
https://www.northwestfirearms.com/attachments/20190925_210928_resized-jpg.620025/

My best 5 shot 100yd group
https://www.northwestfirearms.com/attachments/20190925_210541_resized-jpg.620026/

This is a 4 shot group that measured 1.65" at 100yds and 1.58 MOA. The fifth was a bad flyer that I pulled and I'm not sure where it went but the group showed promise so I just wanted to include another example. I took too long and the guy next to me fired as I pulled my shot.
https://www.northwestfirearms.com/attachments/20190925_210700_resized-jpg.620033/

I still can't believe how well these soft points performed. I'm not sure how much better match ammo would run but I'm very happy with the build.
I just wanted to provide some data for anybody that's interested and I'm happy to try to answer any questions.
Thanks!

Fill me in if you know how to post thumbnails instead of picture links.
Thanks!