So I took my new Grendel upper build to the range yesterday to break it in. I was tuning the gas as well at the same time, so after shot #1, the BCG did not lock back. I was able to manually charge and eject the round. Adjusted the gas out one full turn. Shot #2, and the BCG still did not lock back. I attempted to charge and eject manually, but it was locked up. I could not get the charging handle and BCG to come back. I used a rubber mallet and tapped on the charging handle. After a 8-9 taps, it came free and I was able to charge and eject the round. I re-lubed everything and shot #3. Locked up again. One more shot using a different lower receiver, shot #4 locked up again.
Spot 3 Newest Resized #2.jpg
Spot#2.jpg
I used Hornady 123grn SST's. Toolcraft bolt carrier with a JP headspaced bolt and criterion barrel.
The rifle passed function check and manually cycled and ejected ammo from a mag just fine prior to shooting.
Inspecting parts, the BCG, charging handle and gas tube looked fine.
I did fine this gouge/wear spot (shiny spot) on the inside of the receiver where it is obviously sticking.
What do folks think? The bolt that came with the toolcraft bolt carrier is 2.8795ish" in length and the JP bolt is 2.8805ish"
All opinions and suggestions welcomed.
Spot 3 Newest Resized #2.jpg
Spot#2.jpg
I used Hornady 123grn SST's. Toolcraft bolt carrier with a JP headspaced bolt and criterion barrel.
The rifle passed function check and manually cycled and ejected ammo from a mag just fine prior to shooting.
Inspecting parts, the BCG, charging handle and gas tube looked fine.
I did fine this gouge/wear spot (shiny spot) on the inside of the receiver where it is obviously sticking.
What do folks think? The bolt that came with the toolcraft bolt carrier is 2.8795ish" in length and the JP bolt is 2.8805ish"
All opinions and suggestions welcomed.
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