Ejector swipe on multiple ammo brands

[pnutty]

Hi again;

I’m having a few more issues with my build, specs are:

Aero m5 receiver set

BA 6.5CM 20” barrel rifle length with .0785 gas port with ar15 rifle gas tube in the middle of cutout

Kak 308 bcg dual ejector with small firing pin/hole, oring and 2 ejector springs installed

Kak extended buffer tube 7-11/16 deep with H3 buffer and EA1095 spring 

Cmmg lpk

What is happening is that I am getting ejector swipe on 4 different brands of ammo and a scenario where the extracted round doesn’t eject but stays in the receiver and the bolt travels rearward enough to pick up a new round. If I single load a round the bolt locks on an empty mag but the empty round still stays in the receiver. This build has around 100rds through it so nothing should be worn out.

Ammo is S&B 140g, Aguila 129g, Hornady 140g and my reloads in the Lapua brass which has 42g of staball that puts its right in the middle of the reload book spec.

My unprofessional opinion is that the cases are still expanded while trying to extract and that’s why they aren’t exiting the upper, I doubt it is undergassed because the bolt goes rearward enough to pick up a new round or lock backnon an empty mag.

 

[shooterrex]

I was having similar problems with 1 build. The ejectors in the bcg are they flat faced or rounded on the end?

I replaced the ejector with KAK rounded tip and the gun started running right. Almost seems over gassed and the emptiness are not shrinking fast enough to allow extraction. 

[98Z5V]

Does the pic of the brass directly follow the ammo listed, in order?  Like, left to right?  First ammo listed is the first piece of brass on the left, etc. 

You have a dual ejector bolt, but only one swipe on the brass - and the swipes seen are big enough to catch your fingernail, where you'd have to file them off to reload them.  

That 3rd piece of brass has no ejector marks on it at all, left to right, 3rd one.

[pnutty]

7 hours ago, shooterrex said:

I was having similar problems with 1 build. The ejectors in the bcg are they flat faced or rounded on the end?

I replaced the ejector with KAK rounded tip and the gun started running right. Almost seems over gassed and the emptiness are not shrinking fast enough to allow extraction. 

Yes they are both rounded, and I agree with what you are saying about it not shrinking fast enough.

 

4 hours ago, 98Z5V said:

Does the pic of the brass directly follow the ammo listed, in order?  Like, left to right?  First ammo listed is the first piece of brass on the left, etc. 

You have a dual ejector bolt, but only one swipe on the brass - and the swipes seen are big enough to catch your fingernail, where you'd have to file them off to reload them.  

That 3rd piece of brass has no ejector marks on it at all, left to right, 3rd one.

The brass is randomized in the pic, I shot Aguila, S&B, Hornady then reloads in that order. There are 2 ejector marks on the cases but only one of the ejectors is showing up much more pronounced than the other one.

On the S&B case the marks are on the “cr” and “oo” in Creedmoor but it’s hard to tell from the picture, I can try to get better pictures for you if needed.  But I do not know why one ejector mark is showing up much more than the other one…

Edited yesterday at 10:07 AM by pnutty

[Magwa]

also that bolt looks dry as street pavement, and maybe dragging due to how dry it is soak the bolt in mobile 1 synthetic oil for a couple of weeks the oil will adhere to the metal i the bolt and remain slick but breaking in a new gun you want it dripping wet....

[pnutty]

7 hours ago, Magwa said:

also that bolt looks dry as street pavement, and maybe dragging due to how dry it is soak the bolt in mobile 1 synthetic oil for a couple of weeks the oil will adhere to the metal i the bolt and remain slick but breaking in a new gun you want it dripping wet....

Ok sounds reasonable, I usually put some oil on my fingertip and smear it all over the outside as a film coat but ill do what you said 👍

[pnutty]

15 hours ago, 98Z5V said:

Does the pic of the brass directly follow the ammo listed, in order?  Like, left to right?  First ammo listed is the first piece of brass on the left, etc. 

You have a dual ejector bolt, but only one swipe on the brass - and the swipes seen are big enough to catch your fingernail, where you'd have to file them off to reload them.  

That 3rd piece of brass has no ejector marks on it at all, left to right, 3rd one.

I took the best pictures I could of the case heads, the marks dont like to show up for the camera though. You can see the spots where both ejectors are making an imprint but one ejector is much more pronounced than the other one, why that is I have no idea. I also took a picture of the extractor indent on the case if that would help as well. 
S&B had the least amount of swipe and I could not get that to focus at all on the camera.

[Albroswift]

Soak in mobile 1

See what you have under the extractor- Dougnut, spring, tiny spring inside the spring?

Weigh the H3

The swipes do not look like rounded ejectors

When it locks back does it lock on the bolt face 100% or maybe just the bolt carrier?

100% sure EA1095?

Look through the questions on the waterboarding thread, maybe find a clue there

 

[98Z5V]

21 hours ago, pnutty said:

On the S&B case the marks are on the “cr” and “oo” in Creedmoor but it’s hard to tell from the picture,

That doesn't mean anything, because of springs.  Springs twist when the expand and contract, so they turn things, in motion.  Even if you very carefully lined up every round in the magazine, exactly the same, all the wording directly matching in the mag, same angle - the springs will twist 'em.  Where the marks are, compared to the words on the headstamp - not an indicator of anything.

You have hot loads, plain and simple.  Maybe the ammo is hot - maybe the gun configuration isn't handling the pressure of the ammo you're using.  Something is causing that to be hot ammo in that specific gun. 

[98Z5V]

That extractor mark on the rim - that's telling of a hot load. It was trying to rip that stuck brass out of the chamber. 

So, if it's not the ammo causing this - it's the gun not being able to handle the ammunition.  Something is making all those loads look like hot loads - and it's not always ammo.

Have a chrono you can shoot these thing through?  That will give you some immediate answers, right there.