Still fighting issues.....

[96superflow]

Well, since building by 6.5/264lbc I have been fighting an on going issue with extraction. Doesn't matter the ammo does it with WPA, PPU, Hornady. You name it, it does it.

Upper is a 18" BHW (Stamped) type 1 1-9. Bolt is a NIB Tactical Ambush 7.62x39. Mid length gas system w/ adjustable block

The entire upper was sent to Blackhole Weaponary and they said it functioned perfectly. At first I thought it was the lower, which was build as well. Carbine buffer and spring.

So here is what is happening. A fired casing will get "stuck" in the chamber. The bolt will come back and start loading another causing a double feed. Double feed cleared, slam the bolt home to the fired casing and it will jam causing you not to be able to rack the charging handle like you should. You end up having to slam the buttstock on the ground while pressure is applied on the charging handle. Does a wonder to your hands especially with an aggressive charging handle. It may or may not eject the fired round from the chamber.

So this leads me to:
Casing is stuck in chamber... False, Lock the bolt to the rear and run a cleaning rod down the barrel, Casing floats out.

To me, it leads me to believe I have a type II barrel, and a type I bolt. Causing it to cram the case into the chamber and lockup the mechanism. If you remember from the info the barrel is stamped type I and I purchased a 7.62x39 BCG. I am at a loss.

The gun shoots on point. It is an absolute tack driver. Heck even shot a deer this season and dropped it where it stood. I just want to be able to get to the point of this thing to reach out, (you know, invest into a FFP high magnification scope and stretch its legs as far as I can) I can't do that with the gun still not functioning..... Any help or insight yall have would be great. Thanks!

[A5BLASTER]

So the fired case gets stuck in the chamber, and the bolt runs back and picks up anouther round.

Maybe there is a extractor issue on your bolt.

You said you checked the fired case to see if it was stuck and it checked out as you said it floated, so I'm thinking the extractor itself isn't working properly.

Do you have a heavier buffer you could try.

I could be completely wrong but you never know.

[VASCAR2]

You can color the bullet on a cartridge and put it in the chamber to see if the bullet is hitting the lands. If the bullet is not into the lands I'd try firing one round with an empty mag in the well. If your gas block is adjusted properly the bolt should lock open on the empty mag. If the round still fails to extract you may have an extractor issue if the gas block is adjusted properly. If the gas block is improperly adjusted with to much or to little gas you can have failure to extract. I start with a closed gas block then open the gas block a little and fire. I continue to fire one round opening the GB a little until the bolt locks open on an empty mag.

You should be able to load one factory round into the chamber and be able to extract the unfired cartridge without difficulty. If a factory round does not want to extract you could use a black marker to color the case to see if the shoulder is being jammed into the chamber. You could measure the bolt face depth of your 7.62X39 bolt an see if the face is .125 +or- .001.

You could have gotten an out of spec bolt.

A 6.5 Grendel bolt with .136 bolt face depth would give excessive head space on a barrel chambered for a X.39 bolt. I guess it is possible your barrel is improperly marked but you should be able to check the head space with your x39 bolt/barrel using go no go gauges.

[rabiddawg]

When adjusting the gas block make sure the bolt locks back on the bolt catch and not the mag. Im sure that's what vascar2 meant but was not what he typed.

[VASCAR2]

When adjusting the gas block make sure the bolt locks back on the bolt catch and not the mag. Im sure that's what vascar2 meant but was not what he typed.

Your right, thanks for pointing that out.

[85_Ranger4x4]

A 6.5 Grendel bolt with .136 bolt face depth would give excessive head space on a barrel chambered for a X.39 bolt. I guess it is possible your barrel is improperly marked but you should be able to check the head space with your x39 bolt/barrel using go no go gauges.

I don't think BHW even makes the .136 bolt face, they were one of the first to cook up the .125 one.

[VASCAR2]

BHW coined the term term Type I for .125 and Type II for .136 because they were selling barrels chambered for both bolts. Just recently BHW decided not to offer .136 bolts.

BHW primarily sold .125 but offered a choice of either .125 or .136 for a period of time.

[204 AR]

Sounds like a weak extractor spring to me. Compare to another bolt using thumb pressure to move the extractor and see if it feels weak.

[96superflow]

Yall have definitely given me a place to start. It's terrible to have a tack driving rifle, but yet frustrating as hell to shoot hit. I will try these suggestions and report back, starting at the top and document everything!

[LRRPF52]

You would never be able to fire a single round with a .125" bolt face depth and a chamber reamed for .136" face depth.

BHW jumped into 6.5 Grendel by assuming that the bolts were the same as what the after market was using for 7.62x39. They started offering barrels, many of which have provided more than satisfactory results to the customers.

They either weren't aware of, or thought it wasn't necessary to use actual 6.5 Grendel bolts.

When they acknowledged the difference, they called the after market 7.62x39 bolt a "Type I", and a bolt with a face depth of .136" "Type II", even though 6.5 Grendel and Beowulf bolts had been around since the early 2000s. The whole problem that Colt, and later AA learned about .125" face depth with a cartridge based on the PPC, is that the thicker rim requires a thick extractor lip, otherwise the lip fails under gas-operated primary extraction, which can be quite violent.

The terms "Type I" and "Type II" are best left to ID bolts within BHW's internal company approach to separating the way they look at face depth, not to actual 6.5 Grendel bolts, which have additional dimensional and metallurgical differences to them and the extractors.

The original, real 6.5 Grendel bolts are longer in OAL, 2.810"+. You don't see this with 5.56 or any other bolts that I am aware of. When I first started learning about 6.5 Grendel, I thought AA was just hogging out bolt faces on 5.56 bolts to fit the cartridge, because I had seen this repeated on the internet several times, even here on this forum.

Bill A. explained to me years ago that the bolts are designed and engineered from scratch, then made to AA's specific requirements, with a lengthy QC process as well, involving destructive testing. The alloy is not run-of-the-mill bolt steel either, and they go out of the way to make sure a strong and long-lasting bolt and extractor make it into their rifles and online store.

One big problem that happened several years after 6.5 Grendel started to take off was that Model 1 Sales started making what they called a "6.5 Sporter". They used .125" bolt face depth imitation 7.62x39 bolts that were weak and prone to failure even after a few rounds in 7.62x39 ARs. These bolts would break left and right, with no real good control of processes or dimensions on them. They were popular in the gun show circuit, where vendors can buy super cheap parts, then sell them at their tables to unknowing customers who see what appear to be AR15 parts, when they were nothing even close other than the color and basic shapes.

As with 5.56, parts aren't parts.

[LRRPF52]

OP: What is your gas port diameter?

[96superflow]

Sorry it has been so long to respond... I checked thumb pressure on the extractor, and it was significantly less on the grendel/x39 bolt. I haven't removed the extractor to see if I can swap it out of another bolt, but I will as soon as I can and hopefully get back out and check it again.

I didn't remember what the gas port diameter was, but checked where I bought it from. States .750, and I am pretty sure the gas block is a seekins. I tuned it back when I first put it together shooting one round at a time. Loaded 1 round into the mag, and then kept opening it ever so slightly until it locked back.

[grayfox]

Hi 96, the gas block is 0.750, I think what LR means is what is the diameter of the gas port hole - in the barrel? Typically idk, around 0.084-0.90 give or take (these nbrs are only from memory and it's 1 AM, but thereabouts...)

[LRRPF52]

Gas ports are usually anywhere from .062" to .094".

Anytime I start a build, I now measure the gas port and record that. I recommend everyone do this, in addition to checking that factory cartridges or your intended hand loads fall freely from the chamber after a full seat.

Build doesn't start unless those 2 areas are covered.

[96superflow]

Thanks for yall's clarification. I did not measure it when I installed it. I am going to start with swapping out the extractor spring the next time I head to the range and see if that is the issue in the bolt. I don't build AR's often, really only for a purpose. I originally built the lower/5.56 upper just because I wanted a 6.5 grendel and obtained the parts for the 5.56 at a low cost. I would truly love to see this thing just run the 6.5 upper at all times. Maybe one day to build a longer barrel version and see the comparison with the 18" I have currently.

[grayfox]

Thanks for yall's clarification. I did not measure it when I installed it. I am going to start with swapping out the extractor spring the next time I head to the range and see if that is the issue in the bolt. I don't build AR's often, really only for a purpose. I originally built the lower/5.56 upper just because I wanted a 6.5 grendel and obtained the parts for the 5.56 at a low cost. I would truly love to see this thing just run the 6.5 upper at all times. Maybe one day to build a longer barrel version and see the comparison with the 18" I have currently.

About that extractor spring... sometimes there is a rubber o-ring around it, and some guys just remove that, which allows the extr to operate more easily. you might try that before a complete spring swap-out...

[96superflow]

well I finally got around to trying some other issues. Took the o-ring out, same extracting issues... swapped the extractor/spring with one from a know good 5.56 bcg. was good for a few rounds, then things headed up, and still got the failure to extract. Did switched to one shot at a time and this is what I am looking at from the brass...

PPU Brass


Hornady Brass




What is someone else's opinion on what I am looking at? I feel like it needs some more polishing down close to the neck...

[bj139]

Post a few pictures of your boltface and extractor.

[earl39]

Also is this a .136 bolthead? Have you tried a true 6.5 grendel extractor?

[96superflow]

The barrel is a Blackhole Weaponary 1in9" Type I .264 LBC. (with the .125 headspacing). The bolt is a tactical ambush 7.62x39 bolt (which is supposedly .125 headspaced). i removed the extractor from a 5.56 BCG I had along with its respective spring. Here are the images you asked for.