Intro of me and build issues

Sparkylr308 · June 4, 2022

Hello all. I am new to the forum. Built my first lr-308 pattern rifle. I have built. A few a few 15’s and a 9 but brand new to the LR-308. I am having some issues (which is what brought me to this forum.) I can’t get the dang thing to cycle reliably. I can get it to run 150 gr federal blue box regularly and 180 gr federal blue box regularly depending on which spring and buffer I use but not 168 gr federal sierra match king factory ammo at all. I was able to get it to cycle 2 rounds of Hornady black 168 gr once.
the parts list is:

Barrel Faxon pencil 18in barrel extension LR-308

Rifle length gas system

Kak industries gas block

Kak industries bcg LR-308 double ejector spring slick side

LR-308 carbine heavy buffer kak

guntec carbine buffer

Guntec buffer spring

LR-308 carbine spring kak

Expo arms gas tube

matching Noreen factory billet upper and lower. I have tried a few different combos of buffer and springs. It will run sometimes. As I said I Got 150 gr federal to run consistently with gun tec spring and carbine buffer and 180 gr federal blue box to run with heavy buffer and kak spring. But won’t cycle 168 gr federal at all, no matter the combo. And will sporadically cycle Hornady black 168 gr 308. Any suggestions would be greatly appreciated.

jtallen83 · June 4, 2022

Welcome from Iowa!

Look up that "waterboarding" thread for just a few more details needed. Get more details on the buffers and springs, we have seen people order the correct spring but receive the wrong one, mislabeled. Weights, lengths, and coils counts are a must so the gurus here know exactly what they are looking at.

unforgiven · June 4, 2022

Welcome from Indiana brother.

It's all in the details.

Sparkylr308 · June 4, 2022

Thank you guys! Will do!!

Rsquared · June 4, 2022

Welcome aboard from Maryland.

Armed Eye Doc · June 4, 2022

Welcome to the forum. While you are digging into your rifle, see if you can get the diameter of your gas port in the barrel. Many of them are drilled to small and don't let enough gas through.

Sparkylr308 · June 4, 2022

Thank you! And will do. Gonna take her apart a bit tomorrow.

shooterrex · June 4, 2022

Welcome from KY.

Savage11006 · June 4, 2022

Welcome from Ga! Great group of guys here that'll get that rifle functioning for ya.

BrianK · June 4, 2022

Welcome to the forum.

I can't help you but as you've already seen, others can and will help.

Cunuckgaucho · June 4, 2022

Welcome from BC

MJV83 · June 5, 2022

Welcome from NJ…and as @Armed Eye Docmentioned. It seems like at least 75% of these need the ports drilled out larger. Get all you water board stuff up and these guys will have you up and running in no time at all!! My rifle wouldn’t cycle ANYTHING a single time. Came here, posted my water board stuff, within a few hours @98Z5Vtold me to drill out the gas port to “x” size and went to the range yesterday for the second time and with over 200 rounds down range, not a single issue.
I’m relatively new here too, but these guys know there stuff and will have you cycling better than Lance Armstrong doped out of his mind!! I’m willing to bet, there isn’t a single rifle that these guys can’t get running…so long as you give them the info they need!! Best of luck, and welcome to the site!!

Sparkylr308 · June 5, 2022

Thank you everyone for the responses!! I appreciate it greatly. I figured a few more things out (with your suggestions).
: the gas port is undersized at .089.
.gonna have it reamed out to .096

:the bcg was going to far back and hitting the buffer tube. There are marks on the buffer from the bcg. The marks line up perfectly with the bcg. The buffer tube is exactly 7” inside. And the tube lines up perfectly with the receiver.

. Going to try that quarter trick, as the bcg is for sure going to far back with kak spring and heavy buffer when locked back.

: the thing i am not sure of. Does the gas tube look as if it is going far enough into the receiver?

again. Thank you guys for all your help!

98Z5V · June 6, 2022

That gas tube is too short - better to run the Armalite AR-10 gas tube and have it a little long, than a little too short. You'll need a real Armalite AR-10 rifle gas tube, 15.5" long. Gas port diameter for 18" rifle gas should be 0.096" or damn close, in order to function properly.

Sparkylr308 · June 6, 2022

@98Z5Vi am gonna order one but I am just curious what will that do in terms of benefit? Ensure that enough gas is delivered to the bcg?

shooterrex · June 6, 2022

54 minutes ago, Sparkylr308 said:

@98Z5Vi am gonna order one but I am just curious what will that do in terms of benefit? Ensure that enough gas is delivered to the bcg?

That's exactly what it does.

Sparkylr308 · June 6, 2022

@shooterrexah ok. Thank you. I just wasn’t 100% sure. It makes sense though.

Sparkylr308 · June 7, 2022

update:

I opened up the gas port to .096 with a reamer bit. As it was undersized at .089.

Added 2 quarters as a spacer in buffer tube.

I ordered a armalite rifle length gas tube. Gonna install that when it gets here.

I am having trouble tracking down an armalite ar-10 tube.

28 coils on spring I think? ( could have counted completely wrong to be honest)((the spring is by kak industries)). I use the blue heavy buffer by kak industries that is 5.4 oz. 2.5 inches long. 1/16th in I believe thick spring. I noticed this on my shot rounds.

I got it running pretty well. The only issue I had was it picked up a round and just clicked instead of a bang. Chambered the round and everything. Not light strike though. But other than that if cycled 16 of 20 rounds, that previously wouldn’t cycle at all. So getting there! Any suggestions on what that could be?

shooterrex · June 7, 2022

https://www.armalite.com/SACItem.aspx?Item=10007010&ReturnURL=/Armalite/Product-Category/AR10-Parts-Accessories&Category=4eeff98b-d9a6-40fd-be6b-ab2e44ec1080

If you call them and talk to a real person I bet they can find you one.

98Z5V · June 7, 2022

1 hour ago, Sparkylr308 said:

Added 2 quarters as a spacer in buffer tube.

Each quarter is 0.069" thick. You won't need 2 quarters, 1 will do the trick.

1 hour ago, Sparkylr308 said:

I am having trouble tracking down an armalite ar-10 tube.

Don't do that - yet. Keep the extension you have, keep the buffer you have, BUT!... try using the Sprinco Orange recoil spring first, before you buy more parts that you might not need.

98Z5V · June 7, 2022

1 hour ago, Sparkylr308 said:

Any suggestions on what that could be?

It's a combination of all the things that were going wrong, plus you'll need to shoot it and get it broken in. Solve the other issues (the rest of the issues) first, then run it awhile, then see how it's doing, and give a range report... :thumbup:

shooterrex · June 7, 2022

3 hours ago, 98Z5V said:

Each quarter is 0.069" thick. You won't need 2 quarters, 1 will do the trick.

Don't do that - yet. Keep the extension you have, keep the buffer you have, BUT!... try using the Sprinco Orange recoil spring first, before you buy more parts that you might not need.

The link I sent him was for a gas tube. I thought that was what he was referring to.

Sparkylr308 · June 7, 2022

@shooterrexyes sorry. I meant buffer tube. They seem to be out of stock n a lot of places.

@98Z5V I will take one out then. Ok I will grab that spring. Where’s the best place to get one? Any place better than others? Yes I agree. It needs to break in a bit. Will do.