Help Me Build My Latest AR

General Discussion
1

Okay, so I’m not a huge AR guy, but to this point, I built a 20" PA10 and an 18" PA15, I also have a S&W M&P Sport II with a 16" barrel and no muzzle device.

I was going to reconfigure the Smith, but the way everything was looking, I’d be putting as much into replacing parts and the optic on that one (and it’s perfectly functional as is) compared to just getting a new rifle outright. And 4 guns > 3 guns.

Because I already have two weighty ARs with thicker profile long barrels, bipods, and MPVOs, I want this new build to be light and quick. Acceptable accuracy, but honestly I don’t care if it’s a 4 MOA gun, the others are more for benched precision, this will be a runner and gunner.

I’ve already picked out the barrel, it’s a Faxon pencil profile 4150 nitride with an integral muzzle brake. The slick thing about it is that gives you the benefit of a pin and weld without the hassle, Faxon designed the brake to be thin enough to clear barrel nuts and .625 gas blocks so you’re not stuck with your handguard/gas block combo like you would be with a P&W.

As far as the rest, here’s what I’m thinking

Aero Precision Stripped Slick Side Upper
Forged Sabre Lower, Sabre stock, Hiperfire trigger
Sabre 13.5" handguard
Toolcraft Nickel BCG

Reasoning for the slickside is no forward assist, will save a couple ounces. I wanted to build my lower from scratch, but you can’t do it cheaper than PSA is offering with that trigger/safety/pins combo, so that’ll be it. I don’t have a ton of experience with handguards, I usually just pick whatever comes standard, but I measured the muzzle device and with that PSA piece the end of the handguard should line up right with where the brake starts, maybe a quarter-inch of barrel will show. Should look clean and I like the design, but I’m open to other suggestions. That Toolcraft BCG is the same one I run in my other PSA AR and it’s been great. I thought about getting a “lightweight” BCG, but heard grumblings they can make gassing and buffer selection a pain and can even bump fire if not tuned well, doesn’t sound like something I’d want to mess with (especially if it means paying more for new buffers and an adjustable gas block) to save two ounces when I know the Toolcraft will run perfectly with a standard buffer and mid length gas.

As far as optic goes, I want it to be lightweight, durable, and clear, so I’m thinking this Primary Arms GLx 2x prism. Weighs about 11oz, built like a tank, good eye relief, able to use the Bindon aiming concept for CQB but still reach out to 200m in a pinch if necessary, will still be perfectly usable without battery power so no need for backup irons.

All in all, this build should be 6.5lbs max, dead nuts reliable, tough, and effective from 0-100 with the ability to reach out a touch further.

My question is this: does anyone have any better suggestions over what I’ve listed? I’m open to ideas before I bust out the card and start ordering.

2

If you want to get really good accuracy check out Ballistic Engineering triggers. I owned basically all the high end trigger, I have a lot of them and this trigger blows them out of the water. The owner is a very intelligent young fellow. He redesigned the disconnect in such a way that the disconnect now follows the path of the hammer up and down rather than having the disconnect tether in and out of the pathway of the hammer. What this does is, this makes it mechanically impossible for the hammer to skip the disconnect and cause a full auto situation due to debris getting into the trigger mechanism. They also spaced out the sear surfaces as far away as possible from each other, maximizing the sear engagement while reducing the trigger movement it takes to trip the trigger. This thing is sick, it is the shortest reset trigger on the market right now. I try to tell people about this sick trigger because the company just started. They have two triggers, one is set for 4 pounds and the other one they say the minimum is 2.5, but mine got to 1.5. If you are military, first responder etc, you get 15% discount. I am telling you, you will be shock, this thing is something else. I have it set at 2 pounds on my 300 blackout house defense system. I am not playing with this fools, ready to saw them in half :innocent: https://www.ballisticengineering.net/

3

You can set the adjustable to 5lbs max and 1.5 minimum. By the way, your set up sounds fantastic. I am an AR freak. Also own bolt action and lots of lever action.

4

Seems nice, but not an extra $150 over the Hiperfire nice. I also don’t love the idea of a 1.5lb trigger, I want some resistance there, if for nothing other than safety reasons.

5

You can adjusted up to 5lbs. the other version comes pre-set at 4. Do not get intimidated by low pull, once you practice and practice, you won’t go pass 3lbs. I carry a 1911 lock and cock, 3lbs trigger. Practice Practice Practice and self-confidence.

6

Bud, it has nothing to do with practice or intimidation. Things happen, I don’t want to take any route that could potentially increase the chances of them happening. It’s a safety issue. Hair triggers are for competition guns only here.

And if I was setting it at 4-5lbs, again, there’s no reason for me to spend the money to pull the Hiperfire out of the completed lower. Thanks for the suggestion, but not a practical improvement.

7

No worries, every time I hear AR’s my brain thinks of competition set up. Can not go wrong with Hyperfire, I have two on my set ups.

8

I love a good light weight rifle and you’re checking all the right boxes. The optic you listed has some even smaller and lighter 3x prism siblings I’ve used and been fond of. https://www.primaryarms.com/primary-arms-slx-3x-microprism-with-red-illuminated-acss-raptor-556-308-reticle-yard

I’m really curious about the barrel. I didn’t know that existed but it looks like the best way to get barrel weight down as far as possible. Looks like they also make one with an integral flash hider. Interesting. Triggers are to taste so whatever you like, go for it. Just say NO to lightweight BCG’s. They can make for a soft shooting gun but they’re super picky about working correctly. If you want reliable, get the normal weight. Maybe a stiffer Sprinco Blue spring if you end up running an H1 buffer, too. Brings the spring rate back to balance with the added weight of an H1 buffer.

As for an out of the box thought on the (next) lower, while I know they have some well-documented problems, I have some KE Arms polymer lowers and they cut out around another 7oz of weight.

9

I know about those 3x prisms and I considered them heavily because of the weight, but I just personally don’t think the extra magnification will be really necessary and from every review on them, the eye relief isn’t as forgiving as the GLx 2x and the glass quality is juuuust a hair less as well.

The one that really made me think was their SLx 1x cousins. Those are even a hair lighter than the 3xs and the eye relief is crazy good on them (like red dot levels of good,) but I really think I’d like having the 2x for 50-100m shots and the reticle is a little bigger on the 2x as well, it can be really tiny on the 1x depending on how you adjust the diopter.

Thanks for confirming my thought on the lightweight BCG. I don’t want an adjustable gas block, nor do I want to mess with buffer weights and have reliability be in question. I always gotta remind myself of the KISS method.

I’d consider the polymer lower if I wanted this to be as light as absolutely possible making every possible compromise, but I think I’m willing to trade those ounces for the strength of the forged.

10

I’m confused but what’s new? After look at both websites everything Hiperfire is more expensive. What am I missing?

Also, at what point does a person decide replacing a trigger makes sense?

11

Click on the link for the forged Sabre lower I put in my original post. That whole setup comes with the Hiperfire trigger included. $250 total for the lower, stock, buffer, a Radian safety, anti-walk pins, and that trigger.

To change out the trigger I’d have to buy another one separately. I don’t think doing so would be a very smart use of resources considering the Hiperfire is very good.

I could get a stripped lower and build, but I can’t piece together one as good as that Sabre one for what they’re charging, so it doesn’t really make sense to start from scratch if it’s gonna cost me more.

12

If you want weight savings, go with a shorter handguard. On longer guns, i like 12" handguards because it keeps my hand away from the muzzle.

13

I imagine the difference between a different 12" and the 13.5" I picked out is maybe 1oz. Hardly a big difference maker, but I shoot with my support arm fully extended and having that extra bit of space to keep my fingers away from the barrel is nice. Especially since with a pencil it will be heating up quickly.

14

actually i was thinking about your build and the handguard situation. I was thinking perhaps you should look at Odin Works, and their ultra lightweight handguards. they’re amazing, very lightweight. and they’re a great company that stands by thier products. i highly recommend them.

15

Got the lower ordered today.

I just took a look at the Odin Works handguards per your recommendation. They definitely look light and I’ll take your word on the quality, but I’m iffy on the design. Very busy.

Amusing how the most trivial part of a build is probably the hardest one to make a decision on.

16

I’ve handled a rifle with a carbon fiber handguard, and if you’re rich and want light, they’ll be it. But they’re crazy expensive and I’m not entirely sure how much I trust how well they would handle a ton of heat. This is definitely not the most trivial aspect of your build. That will be whether to use the handguard’s built-in QD cups, or add on. Steel is much stronger than aluminum, so I use the BCM M-LOK cups to get a harder attachment.

@fsuscotsman, I’m not sure there is an exact point where a new trigger is about making sense or not. But it’s a big part of how a rifle feels, and if you are sensitive to that it might be something you want to spend on always. Or never if a mil-spec is fine and you’d rather spend the money on something else. Because it’s such a matter of taste over function people get so worked up for their favorite, but as long as it works and you’re happy with it, I don’t think it really matters. I prefer Geissele flat shoe, like the SD-3G or SD-E, depending if I want a fast trigger or a nice two-stage, respectively. And for my limited brain space I limit myself to those or mil-spec so I know what to expect.

17

You know, I didn’t even think about that, I should get a handguard with a QD cup built in.

18

And yes, BradE is absolutely right about the trigger. It’s ALL preference and muscle memory. If you can keep steady with the pull of a mil-spec and are comfortable with it, then you don’t need to upgrade.

On ARs I like a smoother pull than mil-spec with just a tiny bit of takeup so I can gauge where the break is. I’ve fired some super light triggers with zero takeup, and although they are great for firing quickly, I personally find making accurate shots hard because I don’t know exactly when it’s going to pop.

I’m a fan of the LaRue MBT2 for that reason, shot it a few times, but amusingly enough I don’t have it in any of my builds nor will I in this new one. My S&W has a mil spec trigger, my PA10 and PA15 have the PSA EPT, and this one will run the Hiperfire RBT.

The PSA EPT is a nice little upgrade if you’re used to mil spec. It feels similar, but smoother and slightly lighter. Get one of those and polish the contact points a hair or dry fire it a few hundred times to wear it in.

19

yeah they’re pretty busy due to how light they are. i think they have to be done that way so that they can actually be strong enough to not bend or collapse. their i think it is 02 series is so light i thought the package was empty when i first held it. . lol

20

You’re exactly right. Think geodetics.