Extraction problem AGAIN

[gwtx]

GRR 18?bbl, rifle length gas, not suppressed, no comp, just thread protector. Manufacturer unknown (vendor doesn't disclose).
Intermittent fail to extract with case remaining in chamber. Sometimes picks up the next round and jams it into the case in the chamber, but not always. Has never happened while shooting from the bench. Every time it has happened while trying to make a follow up shot on a hog. If it has not jammed another round I can just cycle it by hand and shoot again. I use a brass catcher that is not easy to remove to see if it's jammed(new one on order) , so sometimes it's a mess. When I first got the upper, my hand loads (mild load) were sticking in the chamber. I load the SST's with 27.5gr ARComp seated 2.248-.249 oal (I actually go by base to ogive) , and was bumping the shoulder back .004? when sizing. I increased that to .005-.006. Didn't help. Did full resize to oem specs. Still sticking. Inserted a new unfired case and it stuck.
Tried some more oem loaded cartridges with same results. All cases were ?in spec?. The only round that didn't stick was the wolf steel. It's smaller than the others, .437 at the base.
If I loaded a new oem round by pulling the charge handle back and let it fly, I had to pull as hard as I could on the charge handle while tapping pretty sharply on the other side with a dead blow mallet. Sooo, I cleaned the chamber with solvent and bronze brush turned with a drill slowly. Then with Kroil on the brush. Then with 400 grit flapper. I checked often until the cases were not tight. They don't fall out, but I can pull them out with a little wire hook easy enough. BCG runs buttery smooth. The bolt locks and unlocks with light pull.
Problem solved???? NO, still fails to extract sometimes. Notice while testing that it didn't lock back on last round a couple times with my handloads. It did better with the oem SST's. Brass is landing 4:30 at 8 to 10 feet with only very small flat spot on the mouth. Removed gas block and cleaned everything in the gas system, block, tube, key, and bolt. Gas port measured .094. Drilled it out to .096 and installed adjustable block. Started with open one round, and went out slowly to wide open before it ever locked back, and then it wasn't consistent. Put the old block and tube back on and it locked back on the oem rounds, but failed to occasionally on my weaker hand loads, but cycled fine. The loads aren't really that weak at 27.5 arcomp. I keep the BCG pretty wet with a clp type lube. It has stock carbine buffer and spring. I like the brass not being beat up, but I don't like walking up on wounded hog and the rifle goes CLICK!
I have a new extractor and upgrade kit on order ( both 4 and 5 coil springs and d-rings, and inserts. The upper had about 100 rounds of wolf steel thru it before I got it, and the extractor showed a good bit of wear. I've probably only shot about 100 rounds since. It had a bit of a ?knife edge? built up on the back edge. I filed it off. It is not damaging the brass at all, and no significant ejector swipes, But, I'm going to replace the extractor, and try the lighter (enhanced) spring first, and go from there. It shoots very good. I shot an SST and an ELD into the same hole, then a wolf that hit less than a half inch from the hole. I know, only 3 shot group, but surprised me. We'll see what happens. Sorry for the long post, but I wanted to get as much info as this old brain could remember on the initial post. I did do a good bit of searching, but didn't find a scenario quite like this anywhere. I have put off posting long enough, but there are so many FTE posts, I didn't want to clutter up the site. Hoping discussion on this post might help someone else with a similar problem as well.
All ideas, comments, and Advice would be much appreciated.
I promise to report/reply the results. Gary

[FRB6.5]

Sounds like a multitude of issues.

This excellent thread a few posts below covers all of them:

http://www.65grendel.com/forum/showthread.php?20396-Several-issues-we-ve-come-to-observe-Failure-to-extract-eject-causes

[A5BLASTER]

Sounds like you have done everything you can to fix the issue, except trying the new parts you have on order now.

My advice when the new parts come in install and test it very well. If it keeps having the problem. You have waisted enough time and money on a unknown product and it is past time to move on too a proven company's barrel.

[lazyengineer]

Sounds like a few modifications and adjustments have been made. If I read that right, there was some filing done upon the extractor? Sounds like the gas system has now been modified as well. What brand rifle is this?

If it were me, I'd pull out and replace the extractor, the spring, and the little O-ring around the spring. Make sure it's stiff: you shouldn't be able to easily move the extractor with your thumb.

Also, in my experience, ARComp can be a funny powder. I've seen it short-stroke in rifle length gas systems in .223 with heavies; both on me and on others.

[VASCAR2]

How does the rifle function with Factory Hornady Black 123 grain ELD-M, Hornady 123 SST or Hornady American Gunner 123 grain BTHP or Federal 120 graing BTHP American Eagle. Factory or reloaded ammo should not be hard to extract from the chamber unfired. Sounds like the bullets in your hand load could be sticking in the lands.

If Wolf 100 grain FMJ fires and extracts that might indicate an issue with the brass case ammo. The chamber might be out of spec (short chamber) which is causing the issue with brass cased ammo.

If I were in your position I’d thoroughly clean and polish the chamber. You can buzz the chamber with a brass brush with CLP or other gun oil. Attach the brush to a cleaning rod and use a hand drill to spin the wet brush in the chamber (some shot gun brushes fit the Grendel chamber). Once clean you can use a barrel mop with Flitz or other polishing compound to polish the chamber.

Once the chamber is clean remove the bolt carrier and drop live cartridges into the chamber. Raise the muzzle and see if the rounds fall out of the chamber. If the rounds won’t fall out tap the barrel to see if the rounds will fall out of the chamber. If you have to use a cleaning rod to push the cartridge from the barrel you either have out of spec reloads or chamber. If factory ammo is sticking in the chamber sounds like the chamber is out of spec.

You can use a black marker to color the tip of the bullet to see if the bullets are sticking into the lands. If the bullets are into the lands the barrel might still be useable if you seat the bullets deeper. Having a short chamber in the 6.5 Grendel used to be fairly common. If the manufacturer uses a worn cutter a short chamber can occur especially with inadequate inspection after machining.

If you raise the muzzle and the cartridges fall out of the chamber then you have a problem with the gas system or extractor. By cleaning and polishing the chamber should eliminate the chances of a rough or poorly finished chamber. Normally brass will show evidence of a rough chamber. Posting pictures help.

It is also possible the ejected cases aren’t clearing the action due to the brass catcher. If the rifle functions flawlessly without the brass catcher then the brass catcher might be the culprit.

[Lemonaid]

"Notice while testing that it didn't lock back on last round a couple times with my handloads. It did better with the oem SST's. Brass is landing 4:30 at 8 to 10 feet with only very small flat spot on the mouth. Removed gas block and cleaned everything in the gas system, block, tube, key, and bolt. Gas port measured .094. Drilled it out to .096 and installed adjustable block. Started with open one round, and went out slowly to wide open before it ever locked back, and then it wasn't consistent. Put the old block and tube back on and it locked back on the oem rounds, but failed to occasionally on my weaker hand loads, but cycled fine."

The above indicates not enough energy in the system.
You could try cleaning the buffer and buffer tube and lube them with a good oil (like synthetic motor oil). Inspection of the buffer and buffer tube may indicate an issue there. Try a different (lighter) buffer? or lighter buffer spring?
Take a good closeup pic of new unfired brass hand cycled and also fired brass (remove carbon with solvent) and post it. Same with the extractor.
There are some excellent pics of what the extractor shape should look like here on the forum and also on Johnny's Reloading bench's Grendel vids.
You will solve this and learn a lot in the process!

[CJW]

This is right down LRRPF52’s alley.

[gwtx]

Thanks for the replies and links. I haven't had a chance to shoot since I posted. It was shooting ok with no problems after all that I have done. I hadn't thought about the ejector pin length/strength, I'll try trimming it a bit to see if that will get the eject pattern up towards 3 o'clock. The brass is just barely flat on the mouth, you have to look twice to notice it.
A5, this is the best shooting new barrel I have ever had. It has shot 3 different oem cartridges, and 3 different hand loads all within 1" of each other. I can't blame the barrel,,,yet.
LazyEngineer, I had not heard that about the ArComp. My load of 27.5 shoots very good, but feels significantly milder than the oem cartridges. I've thinking of "upping" it a little. I don't do any more bench shooting/testing than I have to because of the cost of ammo. I check zero now and then, and shoot a hog 2-4 times a month. I normally have the brass catcher installed, even on the bench unless I am checking to see where the brass is landing.
Vascar, I did clean and ran a home made "flapper" with 400 grit paper till the cases quit sticking. I have measured and checked the distance to the lands with my loads which are 123 sst. They touch the lands at 2.262 oal. I'm seating them 2.248
Lemonaid, I have always thought the gas was a bit weak. The changes I made barely made any noticeable difference. Drilled the port to .096 (it was .094), put the AGB (and new tube) on and had it as far as wide open. Seemed to be even weaker.
Put the original GB back on with a tad of blue loctite.
Cleaned and lubed the bolt. The rings look good, gaps not aligned. No sign of significant leakage around the GB or the key. When I took the GB's off, there was a faint carbon (or oil) ring centered almost perfectly on the port. ????
Thanks again for the replies. I'll report back when I get the extractor & kit, but that still doesn't change the gas situation. I'll keep on Keeping on.

[Kswhitetails]

My first thoughts are

1) chamber rough. Clean and polish for better release of expanded case under pressure.

2) Extractor failure. You already mentioned replacing this, but if your chamber is rough, you're starting ahead of the problem, it will catch up to you. Sounds like you like the barrel, a chamber polish may well clean up and make your issues go away, and leave you with a barrel to be very happy with.

What does your fired brass look like? Any evidence of roughness or failure in post finish-reaming polish?
Gas system checks.
Buffer tube smooth allowing easy travel rear and return? Buffer spring good?

Good luck.

[gwtx]

KS, Thanks. I did the chamber(which was a bit tight). OEM cartridges were "sticky" to remove unfired. I ran 400 grit and polish until they extracted fairly easy. I think that was the major problem. I just got through replacing the extractor, spring, and insert. I used the 4 coil spring and the black insert. The extractor I got has more of a ''lip" than the original one. The original one looked worn down, evn though it hasn't had that many rounds. Only had time to test a few shots. Looks promising, cycled fine, and locked back on last round. Brass landing 4 o'clock about 6 feet away. Shot first round watching the ejection, the next two were overlapping, dead center 3/4" high at 60yds. Brass looks fine. I'm happy for the time being. I appreciate the replies/help. I read the post you made that was sent to me by FRB6.5. Thanks again.

[Mad Charlie]

Brush Research Mfg. sells 800 grit chamber hones for 6.5 Grendel, but if you got satisfactory results with your method,you saved yourself about 35 dollars.

[gwtx]

Charlie, thanks for the tip. Tried to get a bit of a cross hatch pattern with a "satin" finish in the chamber. No bore scope,so hard to tell. Didn't take much to get the cases to extract better. They don't "fall" out, but extract easily by pulling on the bolt with my fingers. Still a bit uneasy with the gas situation. Can't figure out why I couldn't get enough gas with the adjustable block I tried.
Oh well, as long as it cycles, I'm happy. Really like the Grendel, and the horde. Can't figure out why it's not more popular. Political I think. Thanks again, good shootin to ya.

[Kswhitetails]

Glad things are looking up! 400 Grit might be a bit aggressive, you may in time want to re-polish with some compound on a mop, then a case. The walls of the chamber are the sticking point so to speak, so the smoother they are, the slicker your gun'll run.

Good luck! Glad we could help out. Accuracy sounds good too. Enjoy.

[FRB6.5]

As to your problem with the adjustable gas block; it sounds like the system was on the edge of being undergassed already. Depending on the design of the block most adjustables leak somewhat until they have some carbon build up. I think it just exacerbated your gas issue.

[LRRPF52]

For those that might have sticky chambers, if it's just barely holding onto spent cases and could use a chamber polish, get one of the 6.5 Grendel chamber brushes, wrap a patch around it coated with JB Bore Paste, toothpaste, Flitz, or similar polishing compounds, and run the chamber brush in and out of the chamber with a cleaning rod secured in a drill. Go back and forth in-line with the barrel, don't just let it sit there and spin circles.

6.5 Grendel chamber brushes

Once you've polished the chamber moderately (not excessively shiny), clean it out with a new patch and some bore cleaner, clean it dry, clean the bore with a bore brush, and shoot.

If you have a short throat that jams the lands, you'll need to have the chamber reamed and polished. I've had to do a few of these for people who had really short throats.