09-15-2021, 12:48 AM
Klem Wrote:Dean,
Welcome to the Forum.
I am with 55' on this one. If you have checked the chamber with GO/NOGO gauges and yet you have to mortar out a round because it is sticking in the chamber then it is ammunition, not the gun. Confirmed further by you trying different bolts and even a different upper. One thing to note, the gun will fire without a gas system however that normally results in a sticky case in the chamber when manually extracting. You are using a gas system however and if the gun does not load a round into battery manually then it is a not a gas issue.
If it functioned for 20 rds but then started sticking the difference is the build up of carbon. So, the ammunition was barely in spec to start with but then as carbon builds up the chamber becomes unforgiving. The ammunition is either too long in headspace, and/or too wide. Headspace is not just in length from base to shoulder, it is also the clearance around the case (diameter).
On the issue of the two types of Grendel chambers, can you confirm you used GO and NOGO gauges, and both passed. What type of chamber are the gauges for?
Thank you! I'll try to grab some different ammo up if I can find it and check that out. I appreciate all the feedback from everyone. This build has me flustered.