AR15 .17 Rem build ejector markings on cases... Need some help!

[BamaPse]

Well I finally finished my 17 rem build an shot it today with great results! Everything functioned really well and it shot under MOA with factory ammunition. The only thing I did notice that was on my brass, there was a clear indent from the ejector. I am wondering what this could be from. There are no other signs of pressure issues at all, just the mark from the ejector. Could this be a head spacing issue? Below is my build specs as to help the more educated AR builders and fanatics with helping me solve this problem. The ammo that I shot was factory Remington Accutip 20gr.


Upper Build
-Upper Receiver Spikes tactical
-Barrel Shilen 24" heavy varmint 1:10 twist 17 Remington
-BCG PSA Premium Nitride BCG
-Gas block Midwest Industries low pro
-Gas Tube CMG Chrome lined rifle length tube

 

[gj]

I would take a close look at the ejector with a magnifying glass and look for rough edges maybe just needs some serious polishing either that or its out of spec for length,,, just my guesses .....

 

[pondskipper]

I was having similar issues with a build I just finished, I ended up installing an adjustable gas block and adjusting the gas flow way down, I think its mostly a timing issue, like the gun is trying to cycle too soon while chamber pressures are still too high.

look on the spr/sdmr build thread to see what mine was doing and how it acted after the fact.gun)

 

[kfreeze]

An adjustable gas block should take care of that for you. The smaller bore diameter in the barrel changes how much gas is working the action. This happens all of the time when changing from the 223 and 308 that the rifles were designed to run. If you install an adjustable gas block (I like the ones from Odin Works and Black Rain) and then adjust it with your load so that when you fire it with an empty mag in the gun the bolt just locks back after you fire. One click more closed on the gas block adjustment and it wont stay locked back. That has eliminated that problem for me in several rifles. Hope this helps.