Any 5.56 Subsonic Loads Using AA1680?

[robrob]

I know this should really be posted in the "Other Subsonic" forum but I know a bunch of you use AA1680 for 300 Whisper. Do any of you have a subsonic 5.56 load using AA1680? If not do you 1680 experts think it would work with a 72gr 5.56 bullet?

I have a ton of AA1680 that I'm using for the Whisper and I'd love to be able to use it with the 5.56 can I have on order.

Thanks in advance,

Rob

[N310toN170]

In order to get a 77gn SMK COAL 2.200" out of a 16" barrel subsonic, you would have to be at about 30% case capacity using AA1680. That is highly inadvisable.

Spend the $20 to get a pound of any of the powders listed on Hodgdon's site that would get a 55gn subsonic:

55 GR. HDY FMJ IMR Trail Boss .224" 2.200" 4.0 1074

55 GR. HDY FMJ Hodgdon Titegroup .224" 2.200" 3.1 1064 4,000 CUP

55 GR. HDY FMJ Hodgdon Clays .224" 2.200" 3.2 1060 3,700 CUP

These are all very fast burning and would be best served from a bolt action.

[robrob]

Thanks for the quick reply, I think I'll take your advice and pick up a new powder.