Two new custom builds

[Jnv55]

First build:
14.5, 7 Twist with a Fluted Shilen barrel that my friend is doing for me, his brake/muzzle comp... It works as a brake and the flash suppress is WAY better than a birdcage ever though of. I'm also using his AMBI controls he makes and Bolt hold open lever he makes. Bravo co, charging handle, etc, etc.. Forged receivers, nickel boron BC, Magpul MOE buttstock and pistol grip OD green, Magpul BUIS, Troy 15in free float handguards (the barrel sticks out just past the Handguards with the brake on it) OD green and the receivers will be light foliage brown. The trigger will be worked to brake at 4lbs, just right for that set up... For me.
Optics, T1 micro and 3x magnifier

Second build
18in, 7 twist, Shilen fluted barrel, once again my friend is doing the barrel riffling, fluting, etc. Carbine length gas system... Would have used a pistol gas system if I had one. His brake/flash hider, billet receivers, Troy free float 15in handguards (OD) Magpul MOE pistol grip, Magpul ACS-L stock (OD) Jard 2lb trigger, and the same light foliage brown duracoat for the receivers.... (It's similar to Magpul FDE)
I will be shooting my own loads, Nosler 77gr custom comp HPBT rounds.
Optics: vortex viper, FFP, 5-20 MRAD 35mm tube and I will probably try and mount something like an RMR on the tube as well.


Already have an Adams Arms upper (carbine tactical elite 14.5) on another rifle with an 4x32 DOC ACOG, illuminated BDC, on it for optics.
I'll update with pics once complete and once accuracy testing is done.

Update....

14.5in


18in


My friends muzzle comp he makes

[MistWolf]

I would forego the AR trigger "worked" to break at 4 lbs. GI AR triggers can have some very thin case hardening and are intolerant of any kind stoning.

Nickle-Boron carries are nice (I have one) but not needed. Before the O-sanity kicked in I would have suggested just getting a carrier with the standard finish and spending the money saved on something more important, but today, it's pretty much "run what you brung".

If the comp doesn't completely clear the handguard, it's a waste. The gases need to vent free & clear of the rifle to be effective.

Billet AR receivers are more expensive for less strength. Forged AR receivers are superior because the grain flow follows the form of the part.

I love light triggers. I have tuned the triggers of my Remington 700s to within and inch of their lives. They are light, crisp have minimal backlash but will pass the drop test. That said, I feel 2 lbs is too light for an AR, even one used for precision shooting. Being too light can lead to doubling and not properly resetting. A crisp break is far more important than a light pull. A properly lubed AR trigger will feel much better than a dry one.

Choice of Aimpoint is a good one. Magpul makes good stuff.

Carbine length gas system with an 18" barrel? That will increase blow down time and along with the greater pressure, gas port size will be critical and port erosion accelerated. It will be more difficult to tune the rifle to run properly than a mid-length or rifle length gas system. A pistol length system (which is even shorter than the carbine length) would be even worse

[Jnv55]

The brake just clears the handguards and I know what you're saying about the gas length system, but the rifle will be tuned for it... He's dead on the money with the way he does the gas port and the tuning of the rifle. I've got $3100 total combined in both builds, so I'm doing ok in that department.... Especially with the way things are right now
My piston upper with GI trigger brakes at 4lbs and I never have any problem with it, same friend did it that's doing my other rifles.
He's an old Infantry/sniper guy with over 30yrs of building all kinds of weapons, he prefers the shortest length gas system with the way he builds things and I have complete trust in him when it comes to it... He's very good.
2lb trigger for more of an SPR type rifle (for me) is just perfect and the reset is dead on the money.
Thanks for the comments and critiques, I'll have pics once they're finished and once I have got my loads dialed in.
I'll probably go ahead and shoot some of my 75gr rounds I have that I have loaded for my piston gun, I know they are semi decent...

[MistWolf]

You'll do it your way. Going with a shorter gas system, especially with a longer barrel is going backwards on an AR. The system that is the most reliable and trouble free is the rifle length system on a 20 inch barrel. Pressure and heat inside the bore is much more manageable when tapped at that point than it is closer to the chamber.

With a shorter gas system, pressure, heat and thus gas density is much higher and make the action more difficult to tune. Gas cutting at the gas port will be greater. Blow down time is longer. The result is a rifle that will be much more ammo sensitive. If you are going to build the rifle around one load and only use that load, fine. But it makes no sense to do so for no gain in performance.

Look at competition ARs. They are tuned within an inch of their lives and are often finicky. But longer- not shorter- gas system lengths are used because it's more forgiving and give a much softer recoil impulse. Short gas system ARs are notorious for having a sharp recoil impulse.

Whether we like it or not, we cannot escape physics. The margin for error with the shorter gas system is very narrow. You may want to have your guy explain why tapping much hotter gases at much higher pressures is good for an AR and how he plans to delay opening the bolt until pressures in the bore blow down to reasonable levels. Research the trouble guys have getting SBRs with real short gas systems to work reliably.

The reliability of a 2 lbs trigger in a self loading rifle is questionable. Partly because of unreliable ignition and partly because 2 lbs isn't really enough to keep the trigger parts from bouncing around under their own momentum during recoil and operation of the action. Any shooter with experience knows tuning the trigger of a self loading firearm to such a light pull has it's risks.

As I said, you will do it your way and when you put enough rounds through the rifle, you'll learn. If you are only going to put a few rounds through it, we have both wasted our time here. I've already spent more time on this than I should

[Jnv55]

The guy who's doing the build is on here, I'll let him chime in when he gets a chance...

[Jnv55]

I just got out of the hospital, so it will be a minute before I can post any pics or range report... Bell's palsy is a bitch, but at least my dominate eye stays open constantly, ha.
Like I said, I'll get my friend to chime in once he gets a chance

[Quentin]

Hope you're doing better, Jnv55... Stay out of that damn hospital if you can!

I also am interested in what your friend has to say about carbine gas length (or worse, pistol length) on an 18" barrel. I think MistWolf is giving you excellent advice on the too short gas length and too light trigger. I wouldn't be in such a hurry to deviate so far from what is known to work well.

[Jnv55]

Picked them up and they shoot like a dream..... Even the SPR with a CARBINE gas system. They have identical paint, the lighting was just different. Mounted the optics after the pic and punched holes in the same spot using the 75gr loads I have. Working up my 77gr loads now... The 2lbs Jard trigger on the SPR is awesome. I love it. The SBR breaks at 4lbs and its very smooth as well
14.5in


18in


My friends muzzle comp he makes

[saddlerocker]

Looks like a 13" rail on that 14.5", not 15"

Nice looking builds, I like the paint-jobs.

The 18" carbine thing is odd though.
EDIT: Not sure, but from the picture it might be a mid-length?

[SWThomas]

Looks like a 13" rail on that 14.5", not 15"

Nice looking builds, I like the paint-jobs.

The 18" carbine thing is odd though.
EDIT: Not sure, but from the picture it might be a mid-length?

I was just about to post this. A 15" rail would cover the whole barrel and most of the comp.