.264 LBC (Kies upper)--Cases Jam when Firing

[Deplorable]

Hi, Grendel Horde! I have a Kies Custom .264LBC chambered upper (18" SS heavy-profile barrel, mid-rifle-length adjustable gas system) that does not eject after firing over 80% of the time. The extractor does have a really firm grip on the cartridge, but the case seizes up or gets stuck in the chamber to the point that it's difficult to work the charging handle backwards to get it out. The upper does have an adjustable gas block, and I have played with various settings to little avail. Also, the upper receiver has M16 feedramps whereas the barrel extension has M4, but I don't see how that would be responsible for this particular problem.

Looking down the barrel does not reveal any obvious obstructions, but it sort of sounds like the chamber may have been cut too tight? (Thoughts?) If so, what's the best way of repairing it--could an emory cloth in the chamber be used to widen it, or should I just send it to a gunsmith? If the latter, can anyone recommend someone who specializes in .264 LBC (I imagine that most gunsmiths don't have that reamer lying around). Kies promised a 'lifetime warranty' but disappeared without a trace...

So far, I have only tested it with Wolf MPT (brass) and Hornady A-max. I haven't used the newish steel-cased stuff, nor any handloads.

[Rickc]

I have used this successfully on a rough chamber and throat that also locked up when fired

http://www.brushresearch.com/brush-types.php?c1=4

[IceAxe]

What does the brass look like?

[Sticks]

Are these factory loads or hand loads? If factory new, what flavor?

It sounds like the case length is too long (hand loads - not unheard of in factory), or as mentioned above, the chamber is iffy.

[VASCAR2]

I use Flitz polishing compound on a barrel mop attached to a short cleaning rod. I use a hand drill to spin the mop coated with Flitz in the chamber of my 22 rimfires. Works great but I've never tried it on a centerfire. CMMG recommends using a brass brush with gun oil spun in their rimfire barrels to improve function.

Have you checked the gas block for proper alligment over the gas port? You haven't provided much information as to whether the rifle occassionally fails to extract or all the time. How many rounds have been fired in the barrel and what bolt are you using with this barrel. The 264 LBC barrels have been chambered to use 7.62X39 bolts (bolt face .125) and also 6.5 Grendel bolts with a bolt face depth of .136. Was the bolt supplied with the barrel?

[Deplorable]

Hey guys, thanks for the responses (didn't get any email notifications or I'dve responded faster).

Rickc, thanks for the recommendation. Did you use that on a comparable, centerfire rifle, or something lower pressure like 22?

IceAxe, I have noticed a faint circumferential ring-shaped gouge on some brass after it was fired. Let me try to dig some up for photos.

Sticks, these are all factory loads. No handloads. Wolf MPT and Hornady A-Max. I've never used steel-cased ammo. The upper has only a few hundred rounds through it.

Vascar2, it FTEs almost all the time. As for the bolt, I don't know. It's whatever Kies put in stock. I will measure the bolt face today.

[Texas]

Having an adjustable gas port gives pause thinking you may not be getting enough gas to cycle the action.
I have had this problem with chrome lined barrel/chambers which get too much chrome or uneven deposits. A drill with a brass chamber brush has been able to solve the problem most of the time.

[LRRPF52]

Measure your headspace with a Hornady comparator, and check the projectile for land engagement.

Something is wrong.

I put 2 Grendel's together over the holidays using SAAMI chambers. Magically, they ran 100% like all the others I've done over the years.
Ejection was at 4 o'clock, bolt locks back on last round, no issues or complaints.