[Check-raiser]

Try a DSA aluminum BCG for even less reciprocating mass.
Could go 16" Faxon pencil, adjusting gas anyways vs 18"
MI lightweight combat rails are my favorite for weight/cost.
The ultralightweight MI or fostech magnesium save loads of weight.
Save a few bones using a KE arms polymer lower.

 

[Featherweight]

Aluminum BCG? How do they hold up?

 

[DirectDrive]

Pretty new to ARs, and am considering building one for light weight and low recoil. It'll be a range toy, possible groundhog gun, so while I obviously want it reliable, 100% reliability isn't critical.

Sounds like the longer the gas system, the less recoil, so rifle length is probably the way to go. Thinking about the Faxon 18" gunner, rifle length, or possibly the 16" gunner, mid length.

Faxon has a light BCG for $240, while the NBS is only half an ounce heavier, and half the price...

Thinking an adjustable gas block will be necessary, and the Superlative Arms looks to be the best.

Don't know much about the buffer system, and it seems like there is a lot to figure out there. Carbine vs A5 vs Rifle, buffer weight, and spring weight, and how those different options relate to the other less common stuff I'm thinking about.

Seems like a muzzle brake is the best thing for reducing recoil, but I'd prefer not to make it much louder to the shooter.

Don't get all axle-wrapped about recoil.
It's only a .223/5.56 for crying out loud.

If you're new to AR, then think about buying a complete rifle first, and then learn the system.
Jumping into building without good AR knowledge may lead you to assembling a junk-fest of a rifle.
There are a lot of junk parts and un-needed parts in AR World.

 

[DirectDrive]

Try a DSA aluminum BCG for even less reciprocating mass.
Could go 16" Faxon pencil, adjusting gas anyways vs 18"
MI lightweight combat rails are my favorite for weight/cost.
The ultralightweight MI or fostech magnesium save loads of weight.
Save a few bones using a KE arms polymer lower.

^^^
Now here's the kind of junk-fest I'm talking about.
Truth.

 

[MarkCO]

Aluminum BCG? How do they hold up?

They don't. Even dialing down the gas and running them juiced, 5 to 20k. I've tested several. One got to about 10k, including 2 broken bolts. The JP will go to 20k. Guys running the SAC use them for their 5 to 6 pound ARs, but they only use them in the match, not general use.

In the 3GN pro series days, I built a few guys bay guns. Light guns suitable to maybe 200 yards, but they that usually only went to 100. Aluminum carriers, magnesium lowers, fluted 14.5" barrels with pinned comps. 40 grain bullets at 2300 fps. Empty buffers, flat wire springs. They were crazy fast and light, but were good for about 20k, with a few re springs along the way.

The cam path wears out on the Aluminum carriers. Tried roller cams, and that helped. Truly a race car part... Meant to shave weight for a specific purpose, not for general use.

 

[Check-raiser]

They don't. Even dialing down the gas and running them juiced, 5 to 20k. I've tested several. One got to about 10k, including 2 broken bolts. The JP will go to 20k. Guys running the SAC use them for their 5 to 6 pound ARs, but they only use them in the match, not general use.

In the 3GN pro series days, I built a few guys bay guns. Light guns suitable to maybe 200 yards, but they that usually only went to 100. Aluminum carriers, magnesium lowers, fluted 14.5" barrels with pinned comps. 40 grain bullets at 2300 fps. Empty buffers, flat wire springs. They were crazy fast and light, but were good for about 20k, with a few re springs along the way.

The cam path wears out on the Aluminum carriers. Tried roller cams, and that helped. Truly a race car part... Meant to shave weight for a specific purpose, not for general use.

If you're shooting 10,000 rounds or $4-5,000 in .223/5.56 ammo, $160 for a new DSA aluminum bcg isnt much to replace as a disposable part. Those DSA bcgs have gone past that roundage as well.
Besides, it's a bench gun for OP.

Fyi, some LW steel BCGs do not fill the entire port door opening leaving a gap for debris to enter the action. You'll notice a lightening cut on the carrier flush to the rear of the gas key. Examples: NBS, brownells and RTB models.

 

[MarkCO]

If you're shooting 10,000 rounds or $4-5,000 in .223/5.56 ammo, $160 for a new DSA aluminum bcg isnt much to replace as a disposable part. Those DSA bcgs have gone past that roundage as well.
Besides, it's a bench gun for OP.

Fyi, some LW steel BCGs do not fill the entire port door opening leaving a gap for debris to enter the action. You'll notice a lightening cut on the carrier flush to the rear of the gas key. Examples: NBS, brownells and RTB models.

Nowhere near that close to the cost of ammo. Custom loads. The cost is irrelevant if the performance is there, it was. But it meant a MORE aggressive maintenance schedule. When you are shooting for $100K, the failure of a part is not an option. It would be a waste for a bench gun as the weight matters less.

If the gun is properly tuned, no one cares about the carrier filling the port. For a very over-gassed AR, sure, but that is not even in the same ballpark as what I am talking about and totally irrelevant.

 

[Check-raiser]

Nowhere near that close to the cost of ammo. Custom loads. The cost is irrelevant if the performance is there, it was. But it meant a MORE aggressive maintenance schedule. When you are shooting for $100K, the failure of a part is not an option. It would be a waste for a bench gun as the weight matters less.

If the gun is properly tuned, no one cares about the carrier filling the port. For a very over-gassed AR, sure, but that is not even in the same ballpark as what I am talking about and totally irrelevant.

If you're shooting for a 100k prize, just drop a new Al bcg in. Or quick change out the Al carrier for a lightweight steel or full mass carrier and adjust gas. Not a permanent mod.

At 40-50 cents per round FMJ brass cased currently, that's about what most people would pay.

The last point matters if you're in a competition and crud gets inside and yes suppressed/overgassed but atleast the adjustable gas block will help a bit here.
More so something for OP to think about with carrier selection.

 

[USAF_PJ]

The whole concept behind lightweight BCGs is to reduce reciprocating mass. Instead of wasting money for a more expensive lightweight BCG you simply reduce reciprocating mass by reducing the weight of the buffer by removing the internal weights.

Less mass requires less gas to get the BCG moving. Gas is reduced by using an adjustable gas block.

I like reducing mass in the BCG instead, heavier (standard weight) buffer seems to help feeding and lock up sometimes...my 3 gun ARs all run the lighter (way too expensive) JP BCGs with standard weight buffers and work really well. Not the least expensive way to run but seems to work (for me).

 

[rlewpolar]

Exactly. Aren't all ARs "low recoil" (speaking of .223/5.56 caliber obviously)? I wonder what a "heavy recoil" AR is?

Try a 458 Socom AR. Now that has some kick. Similar to shooting a high brass slug out of a pump shotgun. A lot of fun, I love mine. At $2/rd though, it doesn’t see much range time

 

[Syclone0538]

Funny, I've been thinking I need to do something with the barrel and gas block I bought right after starting this thread. I have a Windham I might put it on. Still need a free float handgaurd at least.

I'm amazed at all the confusion my op caused. Maybe if I titled this thread that I was looking for a budget competition gun, then I wouldn't have gotten so many posts that where trying to figure out why, and were basically useless.

 

[nedsled]

Pretty new to ARs, and am considering building one for light weight and low recoil. It'll be a range toy, possible groundhog gun, so while I obviously want it reliable, 100% reliability isn't critical.

Sounds like the longer the gas system, the less recoil, so rifle length is probably the way to go. Thinking about the Faxon 18" gunner, rifle length, or possibly the 16" gunner, mid length.

Faxon has a light BCG for $240, while the NBS is only half an ounce heavier, and half the price...

Thinking an adjustable gas block will be necessary, and the Superlative Arms looks to be the best.

Don't know much about the buffer system, and it seems like there is a lot to figure out there. Carbine vs A5 vs Rifle, buffer weight, and spring weight, and how those different options relate to the other less common stuff I'm thinking about.

Seems like a muzzle brake is the best thing for reducing recoil, but I'd prefer not to make it much louder to the shooter.

Direct answer: 18" with rifle gas is the way to go. Very soft shooter. 100% reliable for me so far. I have a Faxon 18", not Gunner, some other slightly heavier profile that I think might have been discontinued.

Other answer: No 223/5.56 AR15 recoils so much as to be problematic or painful. It seriously is not a big deal. I'm talking about "normal" 16" barrel lengths and up. No idea what the deal is with the 10" barrels n stuff.

Other other answer: A standard BCG is all you need. A nitrided toolcraft for $85 is perfectly fine. Anything else is snake oil

Another answer: You really don't need a muzzle break, but are correct about the noise/concussion. Some guys at the range came up to me and were amazed to find it was just a 5.56. I moved back to a normal A2 flash hider.

Still another answer: You don't need an adjustable gas block.

 

[Singlestack Wonder]

After millions of 5.56 fired over the years I’ve never experienced recoil with an AR-15.

Spend time shooting and developing skills vs. buying gimmicks.

 

[Biggfoot44.5]

It's a .223 ...

What recoil ?

Yeah sure . If you're a 3 Gun competitor, and the level where 0.01 sec on a stage makes a difference, then yeah .

But by Normal Rifle Standards , it already has negligible recoil .

The part I scratching my head , is lightweight bbl , and Varmint Hunting in the same sentence ? Or am I misconstrued something?