Precision load development and adjustable gas block settings

Odysseus1911

Piled higher and Deeper
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Minuteman
Feb 14, 2019
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Arkansas
Not new to reloading, but new to precision reloading for an AR. The setting on an adjustable gas block controls how much gas is diverted into the action and thus affects both muzzle velocity and additional variables like bcg cycling, etc. As such, I would think it would have a significant effect on load development.

Do you do initial load development to find an accuracy node with the gas block closed, then tune the gas block, then go back and re-test the charge weights closest to your node, then fine tune, or what? Is there a generally accepted method, or does everybody have their own way?
 
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YMMV but I typically just tune the gas block to lock back on an empty mag for the lowest velocity load I intend to use for that rifle when starting load development. If your final accuracy load is ~3gr or 4gr more than that load then you probably should revisit the gas block setting before finalizing the load. Also, I prefer to run a dummy cartridge in the magazine so that the last round fired of the group is not with the bolt locking back.
 
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