Keeebs
Member
- Joined
- Feb 2, 2020
- Messages
- 20
New 300blk 8" barrel pistol build. Couple 1-200 rounds. Before I start throwing money at this, I was hoping for some confirmation. I believe the gun is over-gassed and the bolt is cycling to fast. I've taken the donut from the extractor, which caused the gun failure to eject. My next thought is new BCG and buffer/spring. Hoping someone can confirm one of these 2 parts are what I need or am I about to spend money when the issue could be elsewhere?
Observations
The brass has snake bites on neck.
Rim is chewed up way more than any of my factory 556 rifles.
Primers looks fine. 110-150gr is what I have, symptoms on all brass.
Mouth is "D" which seems normal from short case hitting deflector.
Deflector has brass marks pretty low towards the BCG, I would of expected these further out.
Buffer has BCG marks which none of my other 556 have (possible cheap PSA buffer & spring?)
Buffer is chewed up from something.
Upper is all Aero.
https://www.aeroprecisionusa.com/300-blackout-8-cmv-barrel
https://www.aeroprecisionusa.com/750-lo-pro-gas-block
https://www.aeroprecisionusa.com/gas-tube-melonite
https://www.aeroprecisionusa.com/ar15-556-bolt-carrier-group
Lower is PSA lower kit.
Buffer weight is 3oz.
My Images
https://ibb.co/gMMLv61
https://ibb.co/GWTHGnB
https://ibb.co/wdSDc9Y
https://ibb.co/FgwtkVZ
https://ibb.co/1zWZT99
https://ibb.co/yQ2skfm
Observations
The brass has snake bites on neck.
Rim is chewed up way more than any of my factory 556 rifles.
Primers looks fine. 110-150gr is what I have, symptoms on all brass.
Mouth is "D" which seems normal from short case hitting deflector.
Deflector has brass marks pretty low towards the BCG, I would of expected these further out.
Buffer has BCG marks which none of my other 556 have (possible cheap PSA buffer & spring?)
Buffer is chewed up from something.
Upper is all Aero.
https://www.aeroprecisionusa.com/300-blackout-8-cmv-barrel
https://www.aeroprecisionusa.com/750-lo-pro-gas-block
https://www.aeroprecisionusa.com/gas-tube-melonite
https://www.aeroprecisionusa.com/ar15-556-bolt-carrier-group
Lower is PSA lower kit.
Buffer weight is 3oz.
My Images
https://ibb.co/gMMLv61
https://ibb.co/GWTHGnB
https://ibb.co/wdSDc9Y
https://ibb.co/FgwtkVZ
https://ibb.co/1zWZT99
https://ibb.co/yQ2skfm