"Mil-spec only" guys need not read further, this is not for you.

I started out trying to build a carbine with maximum reliability and minimal maintenance. I was going to stick with a standard 16 midlength carbine, but it's evolved to a lot more than that. I ended up with many parts that can be considered "newer technology" compared to most standard builds. I only did this if I thought the part gave a real tangible performance (or maintenance) gain, and not just ones that look pretty in my mind.

Colt upper receiver (cerro forge)
SLR rifleworks 13" rail, factory cerakoted OD
KAC SR-15e3 mod 1 barrel
KAC intermediate gas system, double pinned
KAC SR-15e3 Bolt
JP FMOS bolt carrier
JP one piece gas ring
Rainier raptor
Precision armament AFAB
KAC micro BUIS
Aimpoint T1 2 MOA on larue mount
FTW carbine sling
Surefire scout M600 on haley stategic mount

Colt 6920 lower receiver
Colt SOCOM ambi safety
Geisselle SSA-E
Norgon ambi mag catch.
Vltor A5
Vltor A5H0 buffer
Sprinco green spring




This one shows the double pinned intermediate gas block.

SR-15e3 bolt on the JP carrier. Runs smoother than the KAC carrier and cleans easier. Some people may call this blastphemy.

What I ended up with is by far my favorite rifle. It is extremely soft shooting and handles great. I considered replacing the SSA-E with the 3-gun trigger, but that may speed up the trigger pull a little too much. As it stands, I can get a decently aimed shot off as quickly as I pull the SSA-E. I shot a friend's 3G rifle last weekend and I was not able to get back on target by the time I pulled the 3G trigger again.

As far as this rifle goes, I don't think I will be making any additional changes. I considered a KMR as it follows the lines of the build being of a non-standard material, but I really don't feel like taking off the pins on the gas block again.

I actually finished this a while ago, but wanted to make sure it was well tested. As of now, I have 11k rounds through this rifle. The only stoppages were:

1. At around 7k rounds, it started stovepiping the first shot after a thorough cleaning. I found at that this was due to the ejector spring not keeping up with the upgraded e3 extractor and springs. I replaced the ejector spring with a stronger CS Tubb spring and haven't had a problem again. 2. When tuning the A5, I had a few hiccups while looking for the best spring/buffer combo but with this setup, it's been good for 3k rounds.

So in 11k rounds, the only part that's worn out and needed replacement has been the ejector spring, everything else is going strong. Granted the buffer system and spring were replaced at 8k rounds, but the carbine spring was fine before I did this.

In the end, it would have been about the same price and much less hassle to have just bought a complete KAC, but I didn't start the build intended to end up like this. And this way I can call this rifle completely me custom build. I doubt anyone else has one like this.

as you listed the parts i was thinking why not get a kac- it would have been easier, plus ambi controls.

so was the colt upper/lower worth it

so if this was a "technology" test where are the objective results?

I had no intention of doing this as I built it up. It kinda just turned out this way. A KAC is definitely the better way to do it. I didn't specifically want the Colt receivers either. The 6920 lower I already had and the stripped upper was $120 during the panic. I figured that was a decent price. They look beat to shit, but fit together great. If I wanted another rifle like it, I would just get a KAC.

The results were the 11k rounds and only having to replace the ejector spring. Basically testing various parts together. to see how well they would mesh.

Looks good. For 11k rounds it still looks brand spankin new

Info on sling please

Here's an up close picture inside the upper receiver. The receiver where the rails interface don't really have any finish left.

I haven't abused the rifle, when I go into the woods for hunting, I usually take something else so the outside isn't too beat up. Aside from one test where I went 1k rounds without cleaning, it has been well cleaned and lubed throughout it's life.

https://www.youtube.com/watch?v=1hNsLXZSPPc

My impressions:

Love it. These have replaced my slings on everything except my full on precision rifles. For example: My 18" SPR has a FTW carbine sling but my high power rifle still has a turner.

Even the muzzle brake looks new.

 

The AFAB replaced a DD superior suppression device at around 3k. It has an ionbond finish that holds up very well. I reviewed it against a griffin flash comp a couple months ago and finish was one of the big differences:

http://www.ar15.com/forums/t_3_12/657114_Reviewed__Griffin_Flash_Comp_vs_Precision_Armament_AFAB.html

Nice looking stick.

Thanks for the link.

 

Sure, I'll give it a try. I've never been a good photographer.

I really dig it.  I definitely like the rail and the light mount.

Curious, what's the total cost of the build?

A loud Amen, sir.  Way to intelligently thumb your nose at milspec and produce an advanced and technologically superior rifle with no sacrifice to durability.

Is that BCG black nirtide? I think JP uses QPQ SN nitride over stainless.  Nice.  I would have broken from milspec with a nitride barrel, too.  Oh, wait: I did, but with a nickel-boron inspected and pressure tested BCG.

Nice build.

Let's not worry about that.

But really the sum of the parts listed above puts it around the cost of the KAC mod1 or 2. However I've gone through many many different parts and configurations to get it the way I like it so my cost was a good bit more.

Yes, the JP carrier is QPQ. I swapped that in for the KAC because it ran smoother than the KAC carrier which is just a standard mil-spec. Ultimate accuracy was not one of the requirements for this build so I was fine with a CL barrel. The KAC CHF CL is no slouch either and will hold 2 MOA with M855 and red dot, which is plenty good for a fighting rifle.

I like it.

Nice stick, I would shoot it!!!

I would hit it.

I like it.

Hoping to see round count updates on when and if that barrel starts to wear.

Well done

So... it's not something I should tell my wife about if I start to go towards something like this.  Gotcha.

Very nice! If you had to pick a part that you thought gave you the most benefit which would it be?

Nice set up for sure. the heart of it being the KAC barrel and E3 bolt, I suspect you'll be happy for a fairly long time to come. I have right around 17K through my KAC and still looks as good as it did at 3k rounds.

You say that as if you only have one.