Alright guys i need some help!

[Murraymc711]

Parts list as follows...

18in ballistic advantage barrel
Ballistic advantage 6.5 grendel 2 bolt
Anderson upper
Tool craft BCG
Odin adjustible gas block
Wilson rifle length gas tube
Tested with 2 e-lander mags and 1 dura mag

I'll start this off by saying I'm NOT a gun smith however I've built aprox 50 different guns from 80% 1911s to custom Remington 700 bolt guns so I have a pretty good idea of what I'm doing however I've never had this issue.
Everything went together without issue. Took it out for a test fire with 1 round in the mag and the bcg locked back as it should but the case is left in the chamber . Tried with 2 rounds in the mag and it double feeds. With the gas wide open it will cycle 2 rounds before it starts jamming again.
I have checked gas block alignment 5 times disassembled the whole gun and installed on a known working 556 upper tried all of the above listed mags along with a couple 556 mags just for the sake of scratching my head. I installed a cheap (but working) 6.5 grendel barrel that belongs to a friend and i still can't get this thing to run. Any ideas?

[grayfox]

One thing you can try.
Keep the bolt, but swap the bolt carrier for a non-Toolcraft, even a 556 bolt carrier is fine, and also swap out the firing pin, for a known, non-toolcraft, 556 spec firing pin.
Others may have more insights, but toolcraft has been known to use its own length of firing pin and weird length of bolt (which you don't have, but maybe the firing pin, still), the BA grendel bolt should be proper spec. but swap out the things around it.
I've had a couple of bolt carriers fail to do their job for me... can't really explain but when I put the (offending) bc away in the drawer then things started to cycle right.

Plus... you're using factory ammo to start with, right? Always start your new builds with factory ammo.

[Murraymc711]

One thing you can try.
Keep the bolt, but swap the bolt carrier for a non-Toolcraft, even a 556 bolt carrier is fine, and also swap out the firing pin, for a known, non-toolcraft, 556 spec firing pin.
Others may have more insights, but toolcraft has been known to use its own length of firing pin and weird length of bolt (which you don't have, but maybe the firing pin, still), the BA grendel bolt should be proper spec. but swap out the things around it.
I've had a couple of bolt carriers fail to do their job for me... can't really explain but when I put the (offending) bc away in the drawer then things started to cycle right.

Plus... you're using factory ammo to start with, right? Always start your new builds with factory ammo.

I have tried one standard (psa) BCG out of my 300blk rifle and the one out of my 556. However i used the tool craft pin.
Yes sir i have 40 rounds of box ammo barns and 40 rounds of box ammo Hornady. Gun won't cycle at all with the barns and when loaded with Hornady it will fire and eject 1 round feed the next and jam.

[Murraymc711]

I have shot a total of 80 rounds through it trying to adj the gas block ect.

[biodsl]

Parts list as follows...

18in ballistic advantage barrel
Ballistic advantage 6.5 grendel 2 bolt
Anderson upper
Tool craft BCG
Odin adjustible gas block
Wilson rifle length gas tube
Tested with 2 e-lander mags and 1 dura mag

What's in your buffer tube? Standard rifle spring and buffer?

[Murraymc711]

I have ordered an aero 6.5 BCG and a geissele super 42 braided buffer spring... hopefully i can get this thing fixed. Any 6.5 gurus around central fl want to get together and look at this thing? I have a 1k range at my house.... lol.

[LRRPF52]

Does a factory round of ammunition fall out of the chamber after seated fully, without a BCG in the upper?

I don’t install barrels unless they pass my chamber-check with 4 different dummy cartridges.

If the chamber is tight, that could be causing your problems.

It’s better to figure this out before ever installing a barrel in an upper and learning later the chamber is wrong.

[Klem]

Murray,

I read there's enough gas to lock back on last round, so not a gas system problem. But the case is left stuck in the chamber. And the extractor claw is slipping off the rim rather than pull the case out.

It doesn't sound like early extraction where the case can still be expanded and gripping the chamber. This is more for shorter barrels and gas systems.

I'm leaning towards where 52 is going with this. The chamber might be reamed too tight and even after contracting cases are still hard up against the chamber. Another explanation is a weak extractor slipping off the rim. Or the extractor can't close fully on the rim.

But this does not explain the double feed. It is a new barrel and action so the feeding could be a different issue to the case jamming.

[Murraymc711]

Yes sir. Very first thing i check after a bad 22 nosler build i had several years ago.

@klem
There are heavy extractor marks on the spent casing after firing but again the few times i have gotten it to cycle brass lands at 3 like its supposed to. Fires round 1, cycles the 2nd fires round 2 doesn't extract spent casing and feeds round 3 causing a jam. However most of the time it fires round 1 doesn't extract and feeds round 2 causing a jam.
I have 1 4.5oz buffer and one 3oz I've tried in it maybe going to a h3? Or bolt issue?

[VASCAR2]

Ballistic Advantage is known for using small size gas ports on their 6.5 Grendel barrels. BA assume people are going to run suppressors which is why they use smaller gas ports. There are numerous threads where people opened the gas port or sent their barrels back to BA to get the port enlarged.

Are you currently running a suppressor? If no suppressor the signs for under gassed and over gassed can be the same. I’d check the extractor and if there is no damage to the hook I’d remove the black O ring on the extractor stem and spring. In my opinion with a rifle length gas with no suppressor with 18” I’d check the gas port size. The information I have listed for a 18” Rifle length gas system is .094” minimum. You didn’t mention if your using a rifle length buffer tube or carbine length buffer tube. If your using a carbine length buffer tube I’d use a carbine length spring and supplied carbine buffer (3 ounce). I’d start with the adjustable gas block almost closed and fire one round with no rounds in the mag. Depending on how much if any movement you get on the bolt would determine how much more I’d open the gas block.

I’d try incremental changes making small adjustments and once the rifle cycled and locked the bolt back I would then try adding a round or two in the magazine. If the gas port is properly sized you shouldn’t need the gas block/port wide open without a suppressor. You shouldn’t need a heavy buffer with a rifle length gas 18” barrel without a suppressor. If you still can’t get the barrel to function I’d definitely measure the gas port. I’d also inspect the ejector and spring. If the ejector is not freely moving this could create issues your experiencing.


Here is a link to the google custom search. You can look at the previous discussion on ballistic Advantage barrels with gas issues. You might gain some good information from looking at past threads.


https://cse.google.com/cse?cx=0163689474...cu1o&hl=en

[Konocti's Wigwam]

Ballistic Advantage is known for using small size gas ports on their 6.5 Grendel barrels.

Somewhere online I read that some folks were drilling the port out to .125" to get them to operate correctly.

I don't have a 6.5 Grendel barrel with the gas port exposed, but I do have a 300 blackout barrel that has a .125" gas port on it. I have a 16" 308 barrel that has a gas port that is about 1/2 that size.

EDIT: I got my 12" Faxon barrel today and the gas port on it is about .075".

KW

[Murraymc711]

Alright guys i finally fixed the issue! For some reason it won't let me upload pictures to explain what I'm seeing but it turned out to be the bolt AND extractor. 60 rounds in this morning and zero problems shooting .65 moa at 100 and 1 moa at 200. Rain put a dent in my plans but I'm ready to stretch her legs and see what she's got. Thanks for all the replys and ideas!

[Murraymc711]

New BCG from aero precision fixed the problem. The geissele super 42 H1 buffer smoothed her out.

[VASCAR2]

Good deal thanks for the update!

[Klem]

Murray,

What was wrong with your extractor?

And if that was the problem why did changing everything else make any difference?

[Murraymc711]

Murray,

What was wrong with your extractor?

And if that was the problem why did changing everything else make any difference?

If i could post the pictures it would be really easy to see but essentially the bolt is .012 shorter according to BA tech support than spec and that caused the extractor to sit higher on the bolt than its supposed to.

Nothing i did made a difference that's why i came here asking for ideas/ help. Changing to a adj gas block made it cycle 1 round every 10 rounds but that was pure luck.

[Klem]

Murray,

Interesting, how did the BA techs know it was too short if you still have it (you're talking about posting a photo)?

On their website they claim, "Test Fired before shipping to ensure proper function". What did they say about this? What sort of make-good have they offered?

0.65MOA is superb accuracy; even more so from a cheap barrel using factory ammo.

[StoneHendge]

So they basically sent you a Type 1 (7.62x39) bolt with a .125 bolt face depth instead of a Type 2 bolt with a .136 face depth.

[Steve_evetS]

So they basically sent you a Type 1 (7.62x39) bolt with a .125 bolt face depth instead of a Type 2 bolt with a .136 face depth.

My bolt face on a Faxon bolt is 0.1345" center on the firing pin hole and 0.1335" on the outer edge.