Can anybody point me to a thread or chart showing this?
I've had a 300BLK 8" Noveske barrel on order for a while and want to double check some things.
I've read that a 9" 300BLK matches a 16" 5.56 in terms of energy?

I've built 10.5 5.56 SBRs, knowing I was right on the limit of proper bullet velocity/expansion, and that a 7.5 was not adequate in this area.
As I understand it, the 8" 300BLK is indeed within the proper limits of performance for the cartridge. Correct? Making sure I shouldn't be going with a 10" instead.

Intended/expected effective ranges will be under 75yds. Eventually it will be suppressed.

I went with a 8 inch for my 300. The attraction of having a rifle the same length as a 16" Carbine that was supressed was simply too great. An 8" gets you 90% of the energy of a 16" 556. 9" gets you 94%. The new Barnes black tip expands to 375 yds from an 8" barrel.

Perfect - exactly what I was looking for. Thank you.

I'm building my 1st SBR, so I don't have any credible experience.

However, I went with the Noveske 10" BLK barrel.
The 8" and the 9" just seem to be in the steep part of the curve to me.
I figure that 2" more length is not that much a price to get 300fps.

Anything under 100 yards and especially 75 yards, 8" is plenty. Im getting 2 moa without a rest at 100 yards with subs. If supers are ze-roed at 100 the subs will have a 7-9 inch drop.

I would also get 10 inch with 9 inch rail for a lil longer reach, and overall your like at 17 inches with a suppressor.

Looks more like a little over 100-125 (~2050 vs ~2175, right?)fps going from an 8" to a 10" with that particular example.

I told my dealer I will take the first one that comes in set up as I want it from Noveske, be it 8 or 10 inches long. I am planning on shooting my buddies AAC 9" this weekend if all goes well. Curious to see how it will shoot. He is also running the suppressor that is the predecessor to the one I bought. 762 SD. This is just an interesting little cartridge.

I have a 10" noveske, the extra couple inches adds to ergonomics which improve accuracy. I can keep my elbow straight while holding onto the 9"free float rail. Anything shorter causes you to have to choke up a bit. IMO the recoil is just a little heavier than the 223 when compared to shooting supers out of the 300. MY 762SDN6 mounted on the 51T brake ends up being an 1/8" longer than my 16" colt A2 carbine upper with A2 birdcage hider.

Any pics please if the op don't mind?

Are all of those numbers at the muzzle?

yes, I believe they are. Given testing protocol, I would wager they are 15feet, but essentially muzzle velocity.