220 subsonic BC

[silencertalk]

We shot the Remington subsonic ammo on radar.

G1 BC is 0.720 and reliable to at least 800 yards if you start out at 1000 fps or 1000 yards if you start out at 1050 fps. Even if you start out at 950 fps, it is still good to at least 600 yards. G7 and G8 BCs did not work out as well - at lest not as a single value over the useful range of velocities (Mach 0.95 to Mach 0.75 - which is about 1060 to 837 fps).

Note that this is a lot higher than Sierra reports, but they did not do testing below the speed of sound, as radar is not common and most companies use acoustic targets which do not work at subsonic speeds.

[JPratt06]

Wow that's pretty incredible! Just for clarity, what is the muzzle velocity of the Remington 220 gr. loading from a 16 inch barrel? 9 inch?


ETA: Actually, a tacked thread with *official* ballistics data for every Remington load might be a good reference to have in this subforum. Actual BC's and muzzle velocities from AAC 16" and 9" barrels would be much appreciated.

[silencertalk]

Each batch of the 220 is loaded to 1010 fps on a 16 inch test barrel. That seems to be about 965 fps in an AAC 9 inch upper.

[pb_m3]

Just for reference, 10 rounds out of my Noveske 8" averaged 984.7fps.

Specifics:
Factory Remington 220gr Subsonic
8" Noveske SS 8PT barrel
AAC SCAR-H SD Suppressor

Temperature 76F
Humidity 39%
Baro 29.98
Elevation 686 MSL

Measured with CED M2 Chronograph and Kestrel 4000 weather meter, 10' from muzzle.

Thanks for the precise G1 BC data. I'll plug it into "Ballistic FTE" and see if the data can get any more exact.