First AR-15, 4 - 4.5 lb

[redmist]

Lots of options out there, Sub 5lb can be had with a full mass/Mid Gas system that retains reliability. The titanium will help a bunch, just make sure it's used in the right places. FCG Pins, and Bolt catches are not those places in my mind. Having a decently durable rifle should be priority over weight in my opinion.

Ryan

[bigwagon]

No message

[jstalford]

I have an idea.

Since you seem intent on doing this and money isn't an object, what about starting with a 6720 and replacing parts one or a few at a time.

That way if you have function issues, you will have standard parts as back up and be able to easily troubleshoot.

Plus side is, if everything turns out swimmingly, you end up with two functioning rifles.

Does this 5-lb weight target include an optic or iron sights?

No


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[IronMaiden]

They can be had in both sizes...14.5" Mid Length Evo Ultra Lite .750" C.O.R. VooDoo Barrel...but personally I'd get a BCM BFH ELW, it's not just a weight thing but also a balance thing. (Actually I'd go with a 16" over the 14.5" save yourself some headache).

Not a fan of unitized drop-in triggers, suggest looking at Geissele.

Thanks for the link, I'll make sure they are both 0.750".

I'll try the VooDoo barrel first, if it's totally off I can still buy another one. I'm not expecting to have a "perfect" AR first try.

I thought about the HIPERTOUCH 24 3Gun trigger but ordered the Elftmann 3-gun Match just to try something different. The owner of the company seems to be very helpful in case the trigger needs to be tweaked. I wanted to give him a chance. If it causes repeat issues I'll go back to the HIPERTOUCH or a Geissele.

OP, pass on the Kaiser BCG for a V7. I have both and the V7 is superior in quality and finish. Weight is the exact same.

The Kaiser is advertised with a weight of 7.5 oz and the V7 with 7.9 oz. Not a huge difference. Did you put them on a scale? Did you run both for a while? Did the Kaiser show premature wear?

What about the JP Complete ULTRA LMOS Low Mass? At 5.59 oz it has a clear advantage in the weight department.

I'm looking forward to seeing op's build on a scale.

I'll post the build progress and weight here, unless this thread turns into a useless bashing just because I build my first AR with my own set of requirements away from the norm.

Lots of options out there, Sub 5lb can be had with a full mass/Mid Gas system that retains reliability. The titanium will help a bunch, just make sure it's used in the right places. FCG Pins, and Bolt catches are not those places in my mind. Having a decently durable rifle should be priority over weight in my opinion.

Ryan

Durability follows performance and a low weight in this build. I'm well aware that a lightweight BCG like the JP Complete ULTRA LMOS Low Mass won't last forever. I actually don't shot that much and much more enjoy the planning, building and learning experience. I haven’t even shot my Wilson 308 yet, I'm in no rush.

What do you suggest for the bolt catch and why exactly?

[Uprange41]

Some aspects of your build don't really make sense to me. You went with a 15" rail, when a 9"-10" would have sufficed for less weight, but then you want to lighten what is arguably the most critical part? Go with a standard BCG, flip the KMR here for a 9" or 10". I would also suggest that a Faxon Pencil barrel instead of the one you have. The Faxon 14.5" is lighter by ~5 ounces, even their 16" is lighter than the 14.5" VooDoo. A BAD .625" gas block also weighs about half that of the SLR you have.

[IronMaiden]

Some aspects of your build don't really make sense to me. You went with a 15" rail, when a 9"-10" would have sufficed for less weight, but then you want to lighten what is arguably the most critical part? Go with a standard BCG, flip the KMR here for a 9" or 10". I would also suggest that a Faxon Pencil barrel instead of the one you have. The Faxon 14.5" is lighter by ~5 ounces, even their 16" is lighter than the 14.5" VooDoo. A BAD .625" gas block also weighs about half that of the SLR you have.

I should have added the 15" rail to my list of requirements (which I just did). To stand corrected: this build is not exclusively low weight related. I could have saved a bunch with a poly lower etc. The long rail is for pure esthetic aspects. I could have opted for a shorter barrel but don't want to deal with a trust and 6 month waiting time now that things are going to change anyways.

Thanks for the pointer to the Faxon barrel. I’ll read up on this part and might very well go for it.

Regarding the gas block: the SLR Rifeworks titanium Sentry 7 is adjustable and correct me if I’m wrong the BAD is not. Since this is a build with a low weight BCG I assumed this will be necessary to balance the system accordingly.

[Uprange41]

I should have added the 15" rail to my list of requirements. To stand corrected: this build is not exclusively low weight related. I could have saved a bunch with a poly lower etc. The long rail is for pure esthetic aspects. I could have opted for a shorter barrel but don't want to deal with a trust and 6 month waiting time now that things are going to change anyways.

Thanks for the pointer to the Faxon barrel. I’ll read up on this part and might very well go for it.

Regarding the gas block: the SLR Rifeworks titanium Sentry 7 is adjustable and correct me if I’m wrong the BAD is not. Since this is a build with a low light BCG I assumed this will be necessary to balance the system accordingly.

The BAD is not, but using the Faxon barrel over the VooDoo would buy you (weight-wise) a standard BCG, and you would get any tuning done with the buffer.

[methical20]

If you stick a muzzle break INSIDE of your rail and won't be using a can exclusively, you have no business building an AR. You're running the risk of the end of your rail EXPLODING in your hand.

Get a full mass BCG. Especially if you want your rifle to function.

[IronMaiden]

If you stick a muzzle break INSIDE of your rail and won't be using a can exclusively, you have no business building an AR. You're running the risk of the end of your rail EXPLODING in your hand.

Get a full mass BCG. Especially if you want your rifle to function.

The muzzle break sticks out by about 1.5 inches: (14.5" + 2") - 15" = 1.5". I have seen this combo somewhere else and it worked properly.

[Defaultmp3]

The muzzle break sticks out by about 1.5 inches: (14.5" + 2") - 15" = 1.5". I have seen this combo somewhere else and it worked properly.

The threads on an AR barrel are 0.6", IIRC, so it'd be more like 13.9" + 2" - 15" = 0.9". The problem is, if you're using a brake/compensator, the ports obviously open up before the end of the muzzle device (unless it's a linear comp), so you may very well end up blasting the inside of your rail; for example, if you're using the V7 Furion, it would appear that a port opens up almost immediately after the threads (right around 14.5"), so you'd have at least one port inside the KMR, while the second port would probably clear the rail.

You may want to do a mock-up with your rail, barrel, and muzzle device of choice, since not all 15" rails are actually 15". Since this is a money-no-object built, you may wish to consider a 16" and just cut the barrel down to the appropriate length to get a Hella flush look.