Adjustable gas block, enlarged port

[RWBlue]

I am trying to do a 300-221 AR with adjustable gas block. I think I need more gas to get this gun to run right.

If I drill the port with my home drill, what is the down side?

[Robb Jensen]

You might hit the other side of the barrel, you might make the port too big.

Does your rifle lock the bolt back when empty with the gas block is adjusted wide open?

Most of the time ARs are getting plenty of gas, typically it's more than needed instead of too little. I rarely hear of a gas port being too small, unless the barrel has been shortened.

[PALADIN-hgwt]

xxxxx

[RWBlue]

The gun is built.
The gun has been shot, but I will not call it fully tested. I don’t think it will be fully tested until I have a couple hundred more round through the gun and have it functioning with all the loads. Right now I am at ~100 rounds. Some of these are supersonic and some subsonic. This includes 3 different powders, 5 different weights of bullets. This is a very slow methodical process. Additionally I am using Corbin Simtech gel to catch the bullets. I should note that although I have a chronograph, I haven’t been able to use it because of when and where I am doing this testing. Additionally, I want to separate the upper and the lower and test them separately.

Does your rifle lock the bolt back when empty with the gas block is adjusted wide open? I can get the bolt carriage to lock back properly using light bullet supersonic ammunition. But with the heavy bullet subsonic loads I have tried, the bolt carriage either doesn’t move or doesn’t move back far enough. I expect I will need at lease two different settings.

What happens if I make it to big? I mean the adjustment is made at the gas block not the port? So the port can be oversized and not cause any issues, right?

I don’t plan on doing anything radical until I have tried a few more loads and setting, but I am not seeing a down side to opening the port.

The Wildcat question:
This is a wildcat, but then again it isn’t. There is enough free data on the internet that I could have probably just used it to build my load data, but I also collected data from Hornady and accuratepowder, and I purchased some ammo from a vendor. So with this base of information, I good starting point. Additionally, I have been loading one round, shooting one round, looking at the case, reading the primer, reloading the same brass. And I have had minor issues. I have two peaces of brass that have loose primer pockets. Those round are safe, but just marginally. I am not sure if I would want to shoot them in 99 degree heat of summer, with used brass.