One thing to note about 1680 - its DIRTY DIRTY DIRTY as a sub powder. Especially suppressed. You'll get unburnt granuals all over in your lower.
it works awesome, cycles basically anything, but will result in a lot of cleaning. I do recomend keeping a pound or so of it around when working with blackout subs - for testing reasons. If you're working with a new build and 1680 wont cycle it subsonic - you can 100% guarantee you have a mechanical issue to address!
Lil gun will work great for supers, as well as h110, N110, w296 and even 4227 for heavier supers (150gr above). 1680 will also do good heavy supers (150gr and up) and doesnt seem to be as dirty when run supersonic. Do not use lil gun with cast supers unless you're gas checking them. It burns too hot and will degrade the base of even powder coated/hitek coated bullets and cause leading. I did some testing with it early on and i was spraying molten lead out of the end of my barrel from gas cutting at the port. Yikes! i had to scrape lead off my magnetospeed bayo!
If you can get your hands on some Shooters World Blackout powder (Lovex DO-63) that stuff is another fantastic subsonic powder. As an added bonus its about 3x as clean as 1680 is. You can use 1680 data as a starting point, or i believe SW has load data too. As i understand it, lovex used to make 1680 for AA but lost the contract at some point. DO-63 is their version of the powder, but its a little bit hotter (and denser) than 1680 is. Now its being sold as Shooters World Blackout. IIRC - dont have my notes in front of me - I had to drop my loads about 0.3gr to match 1680 velocity's, but otherwise i shoot it hands down over 1680 these days as it saves me a TON of elbow grease time.
For supers generally focus on 110gr - 135gr bullets. Especially when hunting. For plinking 147/150's will bang steel just dandy and punch nice holes in paper on the cheap. As a friendly note - most .308 dia "varmint" bullets will act more like traditional controlled expansion hunting bullets at 300 blk speeds. So dont panic if you read about people using Vmax or Varmageddons for a Deer bullet. They're designed as varmint bullets at 308/30-06 velocitys where they're cooking along with impact velocity's 2800 fps or so. Slowed down where impact velocity is going to be 1800-2000 fps or so they'll do exactly what we want them to do.
125 SST"s are probably one of the better hunting bullets for the blackout, second only to the 110 and 120 barnes blacktips.
I want to try out the new 135 FTX bullets on some critters this year, but i've had other stuff on the blocks for deer hunting.
theres tons of other options out there, being .308 dia bullets, just be warned that you need to do some homework before selecting your hunting bullet of choice as many/most .308 dia projo's simply arent designed to expand at blackout speeds, so they most often act like FMJ's and will just pencil through.
HTH
