Project lightweight

[rxer311]

Got started on a new project recently. On a whim I picked up one of the KE Arms polymer lowers from Brownells and figured what the hell, might as well go with a theme build called project lightweight. I have most of what I need at the moment, but would like some opinions on some things like lightweight BCG.

So far I have the KE arms lower, an upper without FA or door, and Faxon Gunner profile barrel. Currently en route I have a 2A arms titanium gas block, and a Midwest Industries CRLW Lightweight 10.5" Mlok rail which I chose for its 7.6 oz installed wt. I may even pick up one of the titanium barrel nuts with it to save a bit more on weight. CH is a BCM small latch. Planning on a V7 titanium shorty muzzle brake.

Because I like to do home paint jobs I am also going to coat the whole rifle in tungsten Duracoat.

Really the only things I still need are a trigger and BCG. My question comes to the BCG. I don't really want to mess with adjustable gas blocks but I do want to save some weight. Some lightweight BCG are lighter than others. I could go with a super lightweight and use and adjustable gas key, but again, don't really want to mess around too much. I thought possibly go with a JP lightweight carrier which would save some weight but isn't as light as others and then run a Sprinco Orange spring. Since this is not going to be a suppressor host, I am not too worried about excess gas besides having bolt bounce. Hoping that the Sprinco 2x power spring will be enough to tame the slightly lower weight of the JP carrier.

Or...do I just go with a mil spec BCG?

I know I am over thinking things too much on this, but hey, I called this project lightweight, so I want to see how light I can make it without spending and absolute fortune and also not worrying about taming gas.

How it sits currently.

https://i.imgur.com/zihzHWg.jpg
https://i.imgur.com/JNaIizh.jpg

[Aragorn]

Don’t be afraid of adjustable gas. You can get a titanium SLR sentry and they’re legit. I’ve got a couple, including one paired with a V7 titanium BCG. Also has a JP SCS and an AFAB mini. It is RIDICULOUSLY soft and flat shooting. If you’re not gonna suppress it, you just set the gas block and forget it. I set mine to where it’ll lock back with something weak like PMC or Blazer Brass ammo, unsupported with pressure on the mag, and have never had an issue. I also only shoot 5.56, with the exception of using weak ammo to tune the GB.

[BoilerUp]

Lightweights are fun. I built mine off a 2A Balios.

If you go with a light weight BCG, you'll want an AGB. I also highly recommend SLR. And I think a lightweight BCG and AGB is worth it for a lightweight build. Actually, I generally like that in any build that isn't for duty use as the lower reciprocating mass and tuned gas makes for a softer shooter. I used a Voodoo lightweight BCG but those guys seemed to have dropped off. The JP stuff is good. I use their Low Mass BCG on a 308.

https://photos.smugmug.com/photos/i-Sfm98MM/0/99365d1b/XL/i-Sfm98MM-XL.jpg

[rxer311]

Found a lightweight DS Arms BCG that I picked up. Its not as light as some but still lighter by about 3 oz. Going to run a stronger spring and see how it works. If not I found gas tubes from black river tactical that are drilled to reduce gas flow. they make the ports in different sizes. They are pricey for what they are, but will still be a set it and forget it option where I don't have to worry about adjustable gas. I will let you know how it goes.

[eric28]

Alright, kindly keep us posted

[Creeky73]

Question: if you are running a carbine length gas system, would that be enough pressure being pushed back to ensure that the bcg cycled back regardless of having an AGB or are you still asking for trouble trying to run a lightweight bcg with a standard gas block?

[BoilerUp]

Question: if you are running a carbine length gas system, would that be enough pressure being pushed back to ensure that the bcg cycled back regardless of having an AGB or are you still asking for trouble trying to run a lightweight bcg with a standard gas block?

If you run a lightweight BCG without changing anything else, expect the BCG to cycle faster/harder. You can fix that by adding a heavier buffer, but that defeats the whole point of having a lightweight BCG (reciprocating mass is the BCG + buffer), or having a stiffer spring, which also seems silly. So, what's left to slow the BCG down is to reduce gas. Put another way, as soon as you start reducing weight from the reciprocating mass, you need to start reducing the gas accordingly. Unless, of course, your system is undergassed to begin with.

[Creeky73]

If you run a lightweight BCG without changing anything else, expect the BCG to cycle faster/harder. You can fix that by adding a heavier buffer, but that defeats the whole point of having a lightweight BCG (reciprocating mass is the BCG + buffer), or having a stiffer spring, which also seems silly. So, what's left to slow the BCG down is to reduce gas. Put another way, as soon as you start reducing weight from the reciprocating mass, you need to start reducing the gas accordingly. Unless, of course, your system is undergassed to begin with.

I see. Unless you reduce the gas, you need the weight of the buffer and/or bcg to reduce the recoil. When you can fidget with the gas, THEN you can start meddling with reducing your weights bc there isn't so much pressure slamming everything backwards. Thanks for the info.