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I just built my first Grendel. I chamber a piece of new never fired but full length resized Hornady brass and after ejecting it I can see two very distinct cuts in the rim of the case. My build has a BCA Grendel II barrel and a BCA Grendel II bolt carrier group. Is this common with Grendel's? The brass isn't ruined but I have never encountered this with any of my other builds in 223 or 300 Blackout. What if anything can I do to eliminate the problem? Thanks for any suggestions!
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I had this problem with one extractor which came supplied on a complete upper I bought in 6.5 Grendel. I polished the extractor which helped. I suggest you remove the extractor from the bolt (via pushing out retaining pin) then rotate the extractor on the rim of the case. The extractor should slide easily around the case rim. If it doesn't I suggest you polish the high points on the extractor till it fits the rim of a 6.5 Grendel case. I used fine grit sand paper on my extractor and it seemed to help.
It also doesn't hurt to remove the sharp edge on the ejector which can impede feeding on larger diameter cases.
Sometimes the black O ring on the extractor spring/pin can put to much pressure on the extractor. Some bolts work fine with the O ring others function better without it.
Take a look at this thread it discusses the issue with polishing the bolt and ejector.
Here is a good post on accurate shooter about the reason to do the ejector mod.
Last edited by VASCAR2; 02-23-2018, 08:37 PM. -
Watch this video. Johnny's got the fix
I'll be yer Huckleberry.Comment
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Thanks Vascar2 and Crusty. I did as you both described and as in the video. I also removed the black O ring on the extractor spring and rounded the ejector. I chambered a couple of loaded rounds out of a new E-lander magazine and all seems to be working fine with no cuts in the rims of the cases. I won't be able to fire it until Monday and I'll give a full report after that. Thanks to all you have been a great help!Comment
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My Alexander bolt (designed by the guy who invented the caliber) has an o-ring on the extractor so I assume that Bill thinks it's needed. Don't go overboard with extractor force though - too much extractor force shaves brass off your cases and leaves the shavings on the bolt face to cause other problems. The main thing is that the extractor points need to be rounded and smoothed until cases come off of it easily. If you still have problems after that, an enhanced ejector spring will usually flick them off the bolt nicely.
BTW, did you happen to notice that those two marks on your cases are the same distance apart as the points on the extractor? I've seen a fair amount of range brass with grabby extractor marks so this isn't an uncommon Grendel problem.I'll be yer Huckleberry.Comment
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I started the barrel break in procedure as per Kreiger's web site. I perform this time consuming task with every new barrel and in my experience it pays off in the long run for copper fouling, accuracy and barrel life. Besides a long day at the range is much better than a day at work! I have fired 20 rounds thus far without the O-ring (I have found them to be over kill and not needed in the recent newly acquired bolts I have used for 223/5.56 and 300 Blackout builds) and I polished the extractor points. I have also rounded the ejector as detailed previously in Vascar2's post. That said, I see no marks, scratches or any adverse effects of the extractor on the fired brass. The rife functions without feeding issues from the 10 round E-lander magazines. Ejection is "smart" and out at 4-o'clock. The necks of the fired brass are deformed from smacking the shell deflector or the ejection port itself to the point I may have to force a bullet into the necks, point first to straighten them before attempting to insert them into the re-sizing die. I have cut two coils off the ejector spring and it is still smartly ejecting the fired brass out at 3 o'clock and still deforming the necks. I plan on cutting off at least one more coil on the ejector spring. My goal here is to prevent case mouth deformation and to "potty" train my rifle to pile up my spent brass at 1 0'clock, so that in competition, I'm not hitting the competitor next to me or his score keeper with hot brass. I have done this operation on all of my AR's and it also makes it easier to find your brass! As to accuracy thus far on the BCA barrel (20" stainless with straight fluting), I can see it is coming into it's own. I'll give another report when range time and weather permits. Again thanks to all!Comment
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A better way to tame the eject at this point is to use an adjustable gas block. Or you can put some fuzzy velcro on the deflector's angle surface. Or a heavier buffer. Taking another coil might be a coil too far, so to speak.
As for resizing, hitting the deflector etc won't be a problem. I do make a mental note of the ones with the flat spot on the edge and just raise the case a bit more slowly but there's never been a problem with mine. I've had a few "bad" case dings too. Brass is malleable.
I'm not a total expert on ejection angle but the consensus here seems to be to go for 3-4 o'clock. 1:00 may be a bit under. Maybe one of the pros will also weight in."Down the floor, out the door, Go Brandon Go!!!!!"Comment
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Just did the extractor and ejector mod. It is such a simple fix,...took longer to read how to do it then to actually do it!Comment
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