Ejector Marks in an AR

[minnesotamulisha]

Good Morning Everyone. I've got a 6x6.8 that I'm trying to develop loads for, but it seems every load I work on, I'm getting ejector marks/swipes on my brass.

Initially, I thought I was over gassed. I brought some mild loads to the range and completely closed off my adjustable gas block. No swipes during the single shot phase. As soon as I started to open up the gas block, I would get swipes.

I have tried using a different BCG, with the same results. I don't have another buffer to try, but I'm running the H Buffer, weighing in at just over 5 ounces.

I know a 6x6.8 isn't a real common caliber, but most guys are shooting 32 grains of IMR 8208 XBR with great success.

I'm at 30.4 grains and get ejector swipes.

I do not see any flattened primers.

Brass is both virgin, and 1x fired.

I did clean out my chamber yesterday thinking there may have been grease in it. I'll be loading up more rounds tonight and hitting the range tomorrow to try it out, but is there something I'm missing? Any help would be appreciated.

 

[Fast14riot]

I've had the ejector plunger cause swipes due to simply a sharp edge. Taking it out and running it in a drill against some sandpaper to radius the edge can help. What bolt are you running? I use a LMT enhanced bolt in my 6.8, it has a nicely radiused ejector. Also, what brass are you using? I've noticed that Hornady brass is a little bit softer than S&B made Hornady brass or S&B stamped brass.

 

[Sniper338]

Post pics

 

[minnesotamulisha]

Post pics

I'll post some up after I'm done with work.

 

[minnesotamulisha]

I've had the ejector plunger cause swipes due to simply a sharp edge. Taking it out and running it in a drill against some sandpaper to radius the edge can help. What bolt are you running? I use a LMT enhanced bolt in my 6.8, it has a nicely radiused ejector. Also, what brass are you using? I've noticed that Hornady brass is a little bit softer than S&B made Hornady brass or S&B stamped brass.

The edge on the ejector doesn't look sharp. I've heard about chamfering the ejector hole in the bolt face, but I can't get the roll pin our that holds the ejector in.

All my brass is Hornady, but now that SSA is easier to find, I might stock up on some.

 

[Fast14riot]

Also, what is your ejection pattern? 4 o'clock is where you want to be. I always tune my rifles with a standard weight buffer. You can remove the rubber pad and take some weights out to lighten it up as well. Just replace them with a piece of wood dowel to keep them from moving.

 

[minnesotamulisha]

Also, what is your ejection pattern? 4 o'clock is where you want to be. I always tune my rifles with a standard weight buffer. You can remove the rubber pad and take some weights out to lighten it up as well. Just replace them with a piece of wood dowel to keep them from moving.

Honestly, I wasn't watching it. I was using a brass catcher. I'll check on this tomorrow night.

 

[Fast14riot]

Ejection forward of 3 o'clock generally means over gassed and if ejecting only 12" or so and closer to 5 o'clock means undergassed, which may also induce short stroking.

 

[Rsadams]

On the ar 15 what is really bad is when you see the ejector not only ding the case head but twist and tear into the case head leaveing a twist rip... There could just be some trash under it not letting it compress all the way... Lube the bolt and work it with a piece of fired brass..

This is a common problem that people mistake as pressure signs.. You can even knock The roll pin out and check under the ejector but if that's done i would recommend installing a new roll pin... Normally with oil you can work The gunk out or crush it with out disassembling it..The ar15 actually has different pressure signs than a bolt action... Useing cci standered small rifle primers will flaten way before you get to max pressure...

Look up a company called SPRINCO springs and give them a call they will tell you what spring to put in there.. And their springs will last about forever , normally the life of the barrel they say...

And yes normally you want it chunking brass at the 4 or 4:30 position... If it's throwing them at the 2:00 oclock position or further fowards its normally a sign of overgassed.. Hope this helps and its just a gunked up ejector... I just can't help but think you will also need a stronger recoil spring than one designed for .223

 

[minnesotamulisha]

Here is a picture of my fired brass. I tried to position them so all the damage is located at 9:00.

 

[Rsadams]

Here is a picture of my fired brass. I tried to position them so all the damage is located at 9:00.

Check the ejector for full function make sure there's no trash under it... Isn't that hornady brass fairly soft? I have seen alot worse than that , I am not seeing the twist drag marks that I associate with high pressure in the ar15...... Now that you have some pics I am sure it will make it easy for some one to chime in..

 

[minnesotamulisha]

I've got almost two hours invested into trying to remove the roll pin that holds the ejector in the bolt. It's not playing nice. I've got some oil on it, hoping it loosens up.

 

[Fast14riot]

I assume you are compressing the ejector so it doesn't go flying once the pin drifts out. Also, be careful to use a really good punch, I had one break off and stick in the bolt because it was slightly tapered. Was a Bitch to get it fixed.

That's Hornady made Hornady brass, which is a bit softer (and lower capacity) than S&B made Hornady brass or S&B brass. Otherwise the swipes don't look terrible, probably just a stiff ejector.

Shouldn't need a different spring and buffer for the 6x6.8, I use standard rifle buffer and spring in mine (6.8) and swap uppers on that lower as well.

 

[ballisticdaddy]

Have you tried to adjust the gas block? After I work up a load for any of my AR rifles I back off the gas so it just barely locks the bolt back on an empty mag and it really seems to help with the beating the brass takes.

 

[minnesotamulisha]

Have you tried to adjust the gas block? After I work up a load for any of my AR rifles I back off the gas so it just barely locks the bolt back on an empty mag and it really seems to help with the beating the brass takes.

Yep. Was out yesterday and started with it fully closed, and slowly opened it until it cycled and would lock back. Still having issues.

 

[Richard Coody]

Check the ejector for full function make sure there's no trash under it... Isn't that hornady brass fairly soft? I have seen alot worse than that , I am not seeing the twist drag marks that I associate with high pressure in the ar15...... Now that you have some pics I am sure it will make it easy for some one to chime in..

+1

that brass looks great coming out of an AR. Hornady brass is soft. the factory hornady SSTs coming out of my grendel look worse than that.

 

[Rsadams]

I've got almost two hours invested into trying to remove the roll pin that holds the ejector in the bolt. It's not playing nice. I've got some oil on it, hoping it loosens up.

Not to beat a dead horse but...Just try working it.. Compress it with a piece of spent brass rocking it back and forth oiling it alot and see if its just trash under it... It should compress and you have nothing to lose...

Not extractor problems, there are rings from the ejector present...I just don't see pressure signs... Soft brass and half stuck ejector... Even high dollar bolts get trash in them from the machining process.. I work the crap out of everyone I use before even fireing one shot out of them... As far as it being overgassed that is an easy fix.. See above.. Could be trash or a broken ejector spring.. As fast said use a good punch if you decide to remove it...

 

[shortthroat]

You can also get over gassing from a powder that is a bit too fast for the load. You might want to adjust powder and bullet weight to see the affect it might show. Start with loads known to be appropriate for the barrel length you are shooting. When you open up the gas block even a little, there should be no ejector marks, especially if there is not enough gas to cycle the bolt.

 

[terraMODA]

Could be a headspace issue. If there's too much headspace, the cartridge slams back on the bolt face and you will see ejector marks like that. It has been misdiagnosed as over pressure many times.