Subsonic .300 Blackout Question

[Shodown]

So I just recently finished swapping barrels to a .300 BLK on one of my ARs. Does the ammo have to be marked "subsonic" for it to actually be subsonic? I was told that anything over 200 grain is subsonic, but I can't find anything to verify this. This isn't a huge deal, but I would like to get the full effect of my suppressor with subs if/when possible. Thanks in advance.

 

[Okie4570]

I'm not sure if I've ever seen any subsonic .300blkout ammo that wasn't labeled so.

 

[inactive]

I think anything in the 200 - 220 gr range will be subsonic. I've seen the Remington non-UMC 220 labeled with and without the Subsonic, but it's the same cartridge either way (check the part#, it's the same). Not sure about the UMC but I'm doubtful they worked that load up to be supersonic. For Hornady, they don't always label their 208 gr 300 Whisper as subsonic, but it is per their literature.

Funny how they can't put the same sticker on stuff all the time.

 

[inactive]

Hornady:

 

[Shodown]

Hornady:

I have 2 boxes of the Hornady, but it's expensive ($24 per box of 20). I also have some Remington non-UMC 220 grain that you mentioned in the previous post as well and it was a lot cheaper ($18 per box of 20). I'm just wondering if I can just keep getting the Remington for subs and save some money. Thanks for the replies, guys.