Hello all! New to the Grendel world after the better part of a year of research. I built a lower receiver from parts, and elected to purchase an Aero Precision upper with a 20" barrel, rifle-length gas system.
I had an issue right out of the gate with crazy marks on the case (shooting factory Hornady Black to break in the barrel) that I would otherwise think were pressure-related. Ejector circles with burrs raised up, large extractor gouges on the case head, etc. These have been fixed so far with the addition of a JP adjustable gas block.
I'm still getting some major dents on the case mouth, that appears to be from impact with the deflector. I've been doing lots of reading and searching here on the forum...is this the circumstance where I'd need to trim the extractor spring? I have polished the extractor itself which did cut down on the extractor gouges.
02-17-2019, 06:28 AM (This post was last modified: 02-17-2019, 06:34 AM by outdoorgeneralist.)
After further reading, it seems it's the ejector spring I need to trim, NOT the extractor spring. This makes a lot more sense.
I can imagine that due to the increased diameter of the 6.5 case head, the ejector spring would have more leverage against the case as compared to a .223 case, if the springs are identical.
bj139 Wrote:Are you using a bushing die without an expander? Just wondering how that would work to straighten the necks.
Bj139 - my Redding sizer has no expander, and any dented cases I had sized right out. I measured runout and concentricity with excellent results. All my Grrs have had the ejector spring mod, and no longer dent my cases.
If it's true that we are here to help others, then what exactly are the others here for?
NugginFutz Wrote:Bj139 - my Redding sizer has no expander, and any dented cases I had sized right out. I measured runout and concentricity with excellent results. All my Grrs have had the ejector spring mod, and no longer dent my cases.
+1
I use a Forster without the expander ball, plus the ejector spring mod. The cases are without dents and the case mouth concentric after sizing.
NugginFutz Wrote:Bj139 - my Redding sizer has no expander, and any dented cases I had sized right out. I measured runout and concentricity with excellent results. All my Grrs have had the ejector spring mod, and no longer dent my cases.
Klem Wrote:+1
I use a Forster without the expander ball, plus the ejector spring mod. The cases are without dents and the case mouth concentric after sizing.
Thanks. That's what I would have expected but the rifles I reload with bushing dies are not semiauto so no dents on those cases.
bj139 Wrote:Op,
Stick a piece of sticky back velcro to the deflector to eliminate dents.
I've read to do that, but I'd rather fix the issue causing the problem rather than just padding it.
So far, I've cut off about a coil and a half of the ejector spring, but still have the issue with 4/5 cases. By way of inserting a case under the extractor with the bolt removed, the ejector doesn't feel much less potent than it did originally. For those of you that have done this mod, how many coils did you remove?
02-19-2019, 02:41 AM (This post was last modified: 02-19-2019, 03:40 AM by Londerko.)
The info I got (from Klem i think) was :
Place the ejector in the hole first, then put the spring in after. Then cut the spring flush with the face of lugs, not the bolt face. (I think it was like 3 coils)
Then obviously take them out and reverse the order and install correctly.
I did it and will be test firing it on Wednesday.
Londerko Wrote:The info I got (from Klem i think) was :
Place the ejector in the hole first, then put the spring in after. Then cut the spring flush with the face of lugs, not the bolt face. (I think it was like 3 coils)
Then obviously take them out and reverse the order and install correctly.
I did it and will be test firing it on Wednesday.
The way I did it was place the spring (only) in the hole. When its touching the back of the hole and uncompressed here will be a couple of coils proud of the hole. Cut them off so it's flush with the bolt face.
You don't need the extractor if you do it this way. Beats using Velcro because it fixes the problem, not just the symptoms. Plus these springs are only a dollar or two if you are unhappy with the results.
02-19-2019, 04:17 AM (This post was last modified: 02-19-2019, 04:20 AM by Londerko.)
Thanks for clearing that up klem.
I must have first herd mention of doing this from you. But when I trief it, my ejector spring did not stick out of the hole at all.
So i googled AR-15 Ejector Tuning and found a nice little write up in PDF form at Jebavy.net? And followed the directions on doing it the other way. We will see on Wednesday how it works. And like you said, if I screwed it up its a $1-$2 spring. Worth a try
I'm going to have to try this. When changing buffer weights the changes helped the problem but did not help the the ejector. By the testing with the weights the gun functioned better with the factory AR15 carbine weighted buffer. so the gun is not over gassed correct? Now that I have changed to a fixed stock with the different longer rifle buffer and spring I've got to see how the buffer, spring and longer tube change affects the gun before I throw any more changes to the gun. Good info from all and the PDF with the pictures tells the story.
THANKS
Londerko Wrote:The info I got (from Klem i think) was :
Place the ejector in the hole first, then put the spring in after. Then cut the spring flush with the face of lugs, not the bolt face. (I think it was like 3 coils)
Then obviously take them out and reverse the order and install correctly.
I did it and will be test firing it on Wednesday.
Will be trying this today. If it works, I'll include it on a 6.5 setup video on my youtube channel.
Haven't done it on a 5.56 bolt but there's probably a difference between how far the spring protrudes on on an 5.56mm and 6.5-Grendel bolt. Be careful there.
Having looked at the link (thanks for that) I see he is using a bolt ejector vise tool to hold the bolt. You can also use an old spent case hacksawed off down towards the web. It'll save some time and money.
