turning off gas

[RA223MM]

I was Chatting with a guy at the range and he made a comment about turning off the gas in my AR to make it like a bolt gun. Cleaner brass and cleaner gun. So I did it. I just built the gun and am just fireforming the brass and getting some rounds down the barrel before load development.

I have a couple questions:
-is there any adverse effects on the gun, or precision? I used the brass I’m going to use for reloading, but just threw together the loads with cheaper bullets and powder I no longer use, so I wasn’t able to judge any effects on accuracy
-if I were to turn off the gas during load development, would it effect accuracy, velocity or harmonics of the barrel to find the node, or when testing seating depths?

 

[srt-4_uk]

Shutting off the gas will make the velocity increase since all of the gas is pushing the bullet and none of it is going backwards to cycle the action. Whether or not it makes a difference in groups, I don't know. But I do know that you will see it on a crony

 

[Qazwsx]

during load development you want your "development" conditions as close to firing conditions as possible. use the gas system here.

 

[MotoFlier]

One thing I noticed when I had my gas turned way down was the case neck was denting on one side, I worked the gas pressure up and it went away once the cases were ejecting. You can see the progression as I was adjusting the block.

 

[Sniper266]

As mentioned above, you will see velocity changes. And while im sure cycling your AR like its a bolt gun is cool i bet you didnt buy an AR to have a bolt gun. I adjusted my gas block to cycle reliably with factory ammo and then did all of my load development around those settings.

Additionally I recommend you conduct your load development how you plan to regularly shoot. IE: find a gas block setting that is reliable and keep it. And if you plan to shoot with a magazine use it... i ran into an issue where i did all my load development with 150smks, got .3 moa groups consistently but never fed them into the rifle using a magazine. I then show up on match day only to learn that my rifles barrel extention doesnt like the ultra sleek 150smks from the magazine and i couldnt chamber a single round from the magazine the entire match.

 

[supercorndogs]

Not sure if its common, but I had an Adams Arms piston kit and I would get a about a 2 moa poi shift with the gas all the way off.