*UPDATE* Disappointing outcome - first time out with .308 build

**agr1279** · 04-03-21, 15:32

Originally Posted by georgeib

The gas port sounds like it's good to go, size wise. Make sure there's nothing obstructing it, like metal shavings or debris. Then do the same for the gas tube, gas block, and gas key. Also perform the gas ring check on the BCG.

The weight of the bolt carrier precludes this. If you’re unsure replace the gas rings and be done.

He should put it back together lube the hell out of her and go shooting.

**georgeib** · 04-03-21, 15:56

Originally Posted by agr1279

The weight of the bolt carrier precludes this. If you’re unsure replace the gas rings and be done.

He should put it back together lube the hell out of her and go shooting.

Sounds like a good plan.

**omegajb** · 04-03-21, 17:46

I've seen several 308's with this problem and I swear the mag springs are so stiff that it pushes the round so hard up against the feed lips that it won't strip a new round.

If it's not the gas port you could try cutting a coil in the magazine and see if that helps.
If it doesn't you might have ruined the magazine but it's a cost effective way to troubleshoot.

Sent from my SM-N986U using Tapatalk

**Black_Sheep** · 04-05-21, 19:03

Originally Posted by matemike

Can you pull the ch back and it locks open on empty mag? Rule out the mag and bolt release

Yes, it reliably locks back on an empty mag.

Going into the range session I had the bolt dripping wet. After a half dozen attempts I pulled the BCG and broke it down for close inspection, reassembled it and hosed it down with Ballistol to the point that it was literally dripping. Still no joy.

After doing some research over the weekend I think there's a couple issues happening at the same time. One being the buffer is considerably lighter than it should be, the other is an undersized gas port. I have a heavier buffer/spring combo on order, I will try that before enlarging the gas port. I have a feeling it will need both to function properly.

**1168** · 04-06-21, 06:13

Originally Posted by Black_Sheep

One being the buffer is considerably lighter than it should be, the other is an undersized gas port. I have a heavier buffer/spring combo on order, I will try that before enlarging the gas port. I have a feeling it will need both to function properly.

I don’t know much about .308 guns, but this is confusing to me.

**grizzman** · 04-06-21, 10:06

I just weighed a couple 308 carbine buffers. One is 3.4 oz, and the other is 3.8 oz. Yours does not seem to be lighter than it's supposed to be.

If your rifle is short stroking due to a lack of gas drive, I don't see how adding a heavier buffer is going to improve the situation.

**Black_Sheep** · 04-06-21, 12:44

My understanding is the heavier buffer will slow the cycling speed of the bolt. The gurus on the .308 forum all advocate running a heavier buffer along with a larger diameter gas port. Several threads addressing the same problems I have experienced report reliable functioning after increasing the port size and running the heavier buffer.

I got an email response from WC stating:

We set up our gas ports to run with carbine buffer systems (3.8 ounce carbine buffer and AR10 carbine spring) Standard (non adjustable) gas blocks are recommended. If your gun is short stroking with this setup you might might have a burr in the gas port or it might need to be opened by a couple of thousandths. A good gunsmith can assist you with that. Thanks!

The gas port is unobstructed, I checked it as well as the gas block and gas tube. So yes, it is probably undergassed. It’s going to require some trial and error to sort out, apparently at my expense.

**grizzman** · 04-06-21, 15:54

I personally wouldn’t immediately jump to a permanent barrel alteration until all other possible causes have been eliminated.

You’re certain the gas block is installed properly, so that’s probably not the problem. Have you investigated the BCG? How about the BCG’s interface with the gas tube?

I’d Wilson says the gas port is appropriate for the buffer you’re using, then it shouldn’t need opened up further. I’d be surprised if they drilled it to the wrong diameter.

Have you tried any other ammo?

**Black_Sheep** · 04-06-21, 19:05

Originally Posted by grizzman

I personally wouldn’t immediately jump to a permanent barrel alteration until all other possible causes have been eliminated.

You’re certain the gas block is installed properly, so that’s probably not the problem. Have you investigated the BCG? How about the BCG’s interface with the gas tube?

I’d Wilson says the gas port is appropriate for the buffer you’re using, then it shouldn’t need opened up further. I’d be surprised if they drilled it to the wrong diameter.

Have you tried any other ammo?

I’m going to talk to the gunsmith when I pick up my parts from Cerakote on Friday. I’m not real hip on altering the gas port, but I think it’s inevitable. What really sucks is unless you somehow get it right on the first attempt, dialing it in might require multiple trips to the range, disassembly, trips to the gunsmith, etc...

When I removed the gas block to measure the port there was a nice concentric ring of carbon around the port so I’m confident that the alignment is GTG and the dimple is in the right spot. The end of the gas tube is properly centered in the cam pin cutout and free of obstructions. There’s very light carbon residue where the gas tube engages the gas key, leakage appears minimal. The BCG has no unusual wear and the bolt gas rings are tight, I’m not sure what else to look for. The bolt face is about 1/4” behind the ejection port with the CH pulled all the way to the rear. It also locks back on an empty mag. Unless I’m doing something wrong, all the basic checks are good.

I used MagTech M80 spec ammo the first time out, I have some S&B, PMC and Privi Partisan M80 spec to try on the next outing. I found a box of Federal Premium Match ammo which I will also try. Based upon current ammo availability I really need this thing to run on anything I can feed it.

It’s frustrating because I didn’t cheap out on the components, it’s just going to take some effort to sort out. Building a rifle is a lot like building a Hot Rod, you just have to find the right combo...

**1168** · 04-06-21, 20:05

Carrier key screws?

I only personally know of one rifle where a gas port on a reputable barrel truly had to be opened (and wasn’t made that way on purpose). It was a .224 Valk using a high-end barrel. Short stroked, so the owner dumped the weights out of the (rifle length) buffer, and it cycled. Barrel maker warrantied it and opened the port.