Subsonic 5.56mm Ammo

[MX5]

Does anyone have any data or can point me to a reliable source for reloading data on 5.56 subsonic ammo? I'm well aware that current sub ammo will not function the BCG of an AR and the weapon platform is essentially a single shot. This project is focusing on subsonic first round capability followed-up with standard velocity ammo in AR mags. Also, there's the use in a bolt gun in which all rounds could be subsonic. I'm working in conjunction with another forum member to first develop good subsonic data for AR type and bolt action type weapons. Then, we're looking at an R&D project for a functioning, dedicated subsonic suppressed AR upper.

[rob_s]

Can I ask why you wouldn't just use 9mm? Besides in the bolt gun, obviosly.

If you acknowledge that all subsonic rounds, regardless of size, shape, weight, etc. must be below 1000 fps (as an easy approximation), and you understand that momentum = mass x velocity, would you rather have a 147 grain bullet traveling at 1000fps or a 55?

Also, be aware that 5.56 rounds at subsonic velocities are likely to drop quickly, negating any long-range accuracy advantage they may have had over 9mm.

[DRich]

I experimented with sub-sonic 5.56 a few years ago. Quickly realized I had a very expensive, centerfire .22LR and decided it was a foolish idea.

[PALADIN-hgwt]

xxxxx

[MX5]

We're very aware of JD Jones efforts with the Whisper project. We're not reinventing the wheel - just taking it in another direction. 55 grains wasn't specified.

[rob_s]

No matter what weight 5.56 bullet you use, you're still going to have a projectile, traveling at the same max speed, with 1/3-1/2 the mass.

I'm still curious as to the application for doing what you're after.