Help

[MNBob]

I am breaking in my new 300blk upper and I am getting blow back in my face and my cases are coming out in a D shape. Any ideas?

 

[Chopperdrvr]

Looks like a little over gassed. Are you running a suppressor? Do you have an adjustable gas block?

 

[MNBob]

Looks like a little over gassed. Are you running a suppressor? Do you have an adjustable gas
It will be suppressed waiting for tax stamp.

 

[djones]

first of all, let me say that i am no where near proficient with diagnosing gun problems. i can barely shoot one, let alone trouble shoot one. however, your symptoms suggest over gassed. if you're not suppressed yet, then you really have a gas problem. adding an adjustable gas block addresses that problem. a heavier buffer and buffer spring help with other symptoms, namely the bolt hitting the rear too hard.

your brass is probably dented from hitting the shell deflector too hard. i bet it lands pretty far away in the 1:00 area??

there are ideal ranges for barrel length for a given gas tube length. you may want to make sure yours is not at the outer limits of that range. your gun may have been optimized for subsonics. when you take off the old gas block, you can also check the size of the gas port and see if it's over sized.

if everything is set up properly and you still have blow back in your face, gas buster charging handles are supposed to help. there is also a diy patch for bedding regular gas blocks that redirects the gas escape route.

dang... maybe i AM a gun expert!!!

 

[ZenArchery]

You got gas issues or your ejector just needs some time to break in. As for the brass your sir will get them back into shape.

 

[MNBob]

first of all, let me say that i am no where near proficient with diagnosing gun problems. i can barely shoot one, let alone trouble shoot one. however, your symptoms suggest over gassed. if you're not suppressed yet, then you really have a gas problem. adding an adjustable gas block addresses that problem. a heavier buffer and buffer spring help with other symptoms, namely the bolt hitting the rear too hard.

your brass is probably dented from hitting the shell deflector too hard. i bet it lands pretty far away in the 1:00 area??

there are ideal ranges for barrel length for a given gas tube length. you may want to make sure yours is not at the outer limits of that range. your gun may have been optimized for subsonics. when you take off the old gas block, you can also check the size of the gas port and see if it's over sized.

if everything is set up properly and you still have blow back in your face, gas buster charging handles are supposed to help. there is also a diy patch for bedding regular gas blocks that redirects the gas escape route.

dang... maybe i AM a gun expert!!!

Thank you for the help.