Charging handle lock up
#1
New to forum:
I recently built a 6mm ARC with a Ballistic Advantage barrel mated to a Ballistic Advantage 6.5 Grendel bolt and bolt carrier. Using RCBS small base dies I loaded and chambered 108 ELD bullets using H4895@24.5 grains. Velocity 2454 SD=6. The issue is that the charging handle locks up after firing and is extremely difficult to pull back. I sometimes need to "mortar" the gun to remove the fired case. The same happens after putting a fired case into the chamber and attempting extraction. A new unfired Hornady case extracts without a problem. The charging handle operates smoothly.
I placed a 6.5 Grendel bolt/carrier from a LaRue 6.5 Grendel AR that I have. No issue with the charging handle being stuck. Case ejects smoothly.
My conclusion is an issue with the Ballistic Advantage bolt. I measured fired cartridge base to datum(.350) at 1.1880 on brass fired from the Ballistic Advantage bolt group vs 1.1915 for brass fired with the LaRue. bolt. Is the BA bolt out of spec resulting in compressed headspace making case removal difficult?
Reply
#2
Have you measured the depth of the bolt face (.135")? That might give you a clue as to the bolt being out of spec. Do you have a 6mm ARC headspace gauge?
The trick is growing up without growing old. -- Casey Stengal
Reply
#3
I don't have head space gauges. since they are hard to find and would be used only once. (Maybe a field gauge would do it.) But measuring the depth of the bolt face makes complete sense. The Ballistic advantage bolt =.131 and the LaRue = .135. The difference .004 which corresponds to my case head to datum line measurements with a difference of .0035 rounds up to .004. I will call Ballistic Advantage to get their thoughts tomorrow. As I understand the SAAMI specs are 1.1901 Min to 1.2001 Max- case head to datum (.350).
Reply
#4
There ya go! BA needs to replace your bolt. I had a similar problem with my Grendel AR. One bolt I have won't close on a go gauge. It's in my junk box.
The trick is growing up without growing old. -- Casey Stengal
Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)