300Blk 220g subs. Loading help. W/ CFE300Blk

[nikdanja]

I’m wanting to be on the upper scale of speed while still remaining sub sonic with this powder/bullet combo. A local shop makes these bullets in house for the 330blk so I’m not ordering any bullets offline to load from.

I have a suppressed 8” barreled 300BLK AND WANTED a good starting point.

 

[ebert]

my 16 inch barrel I load between 11.5 and 12 grains of cfeblk.

 

[toxic]

I have a 7.5", and I run 10.8gr CFEBLK with 220gr scenars. Puts me right at 1050 fps.

 

[ebert]

around 11.8 and 11.9 you can hear the sonic boom less than that and there is no sonic boom. I don't know what the velocity is

 

[Glassaholic]

It depends on your altitude as well, speed of sounds changes with elevation. What altitude are you at OP? Here's a chart that will help.

 

[nikdanja]

Thank you!

 

[jambau]

11.2 with my 16" bolt action. 1011fps with the Maker Rex 220 gr . Caution: Make sure you have the twist to shoot the long heavyweights