I was testing supersonic 147 grain loads today on a rifle with a BRA piston upper.
They’re not exactly hot and there’s no excessive pressure signs on the cases.
However did dawn on me that I had been using subsonic loads previously and exclusively.
I’m pretty sure the upper came with a buffer but I’m not so sure it came with a spring.
There is a hole in the bottom of the bolt carrier group and if the buffer goes back far enough it gets stuck on the buffer retaining plunger (whatever hell it’s actually called).
The spring that was in the buffer tube had a green end.
Anybody know what spring I should actually be using with this if I want to shoot supersonic loads?
(these loads are 147 grain military surplus bullets with 16 grains of H110 behind them.)
They’re not exactly hot and there’s no excessive pressure signs on the cases.
However did dawn on me that I had been using subsonic loads previously and exclusively.
I’m pretty sure the upper came with a buffer but I’m not so sure it came with a spring.
There is a hole in the bottom of the bolt carrier group and if the buffer goes back far enough it gets stuck on the buffer retaining plunger (whatever hell it’s actually called).
The spring that was in the buffer tube had a green end.
Anybody know what spring I should actually be using with this if I want to shoot supersonic loads?
(these loads are 147 grain military surplus bullets with 16 grains of H110 behind them.)
Last edited: