I just got my conversion done of my AR .223 over to the .300 Blk and had it sighted in by the gunsmith that switched the uppers. He used 150 Grain Subsonic FMJ ammo and all I could find today was 208 Grain Subsonic and 125 Grain Supersonic. I bought 2 boxes ea of both but really don't know if I am going to be shooting w/ blind folds on now that I couldn't find 150 grain. Any advise would be greatly appreciated!

150 grain subsonic? That's a very light bullet for a sub. Also, if it's in an AR, that will be hard to get it to cycle.

The differences are simple. The subsonic ammo runs below the speed of sound (which is about 1100 fps) and is a reduced load. The supersonic ammo will be a full power load running at top speeds for that bullet.

Depending on the rifle and ammo, your sub rounds will impact about 6"-15" lower at 100 yards than your supersonic ammo. It's simply due to the much slower round. You will want to sight in for 1 or the other. If you plan to switch back and forth, you will need to change your scopes zero each time. Having a mil or moa scope with turrets helps this transition.

Your 125 super ammo will impact high about 6"-15" above where the 150 subs are sighted in at. Let me know if the 150 subs will cycle, I'm curious. And if they do, how clean/dirty they are shooting suppressed.

IMO, the subs are for fun, and the supers are for hunting. Shot placement and knowing your bullet trajectory in the subs is critical to making lethal shots. A 300 blk out sub round is about like shooting a 45 ACP, instead with a 308 bullet that doesn't expand.

I have lots of ammo options available below.

Supersonic: http://dallasreloads.com/product-category/300-black-out/

Subsonic: http://dallasreloads.com/product-category/300-black-out-subsonic/

If you're not running a suppressor on the front, I don't get the advantage of using subsonic.

This is the loads that were used to sight in my conversion. No real place that says if it is sub or super but really don't want to go hunting tomorrow without having it dialed in.

Chad, would you be available in the morning to get some 150 Grain Super? I am going to leave Las Colinas around 11 at the latest

I'd suggest staying away from FMJs for hunting. It's your party though.

The Freedom ammo is a supersonic load, not a subsonic load. It is a cheap plinking load. I wouldn't recommend it for hunting, but if that's all you have, it will work.

I have 125 and 150 Nosler BT, 125 SST, 150 FMJ, 115 Berger, 110 V-max, as well as others in stock. Sure, just call me tomorrow morning. I will be around.

No it wasn't for hunting at all just sighting in and having some rounds to shoot with. Hence why I was shopping for some comparable grain loads 2 days ago before I went out in the field. Since it was sighted in at 100 with 150 grain, thats what I'd like to get. What am I looking at for price?

Thanks again and a number to contact you with,

Mike

One interesting feature of target shooting with the subsonic is elevation practice without having a long range. My 308 is zeroed at 100 yds with normal ammo. When I use subsonic, I have to go up 2 1/2 mills @ 50 yds, which with normal ammo corresponds to 400 yds. At 100 yds I have to go up 5 1/2 mils which corresponds to 650 yds with my normal ammo. Granted the wind drift isn't the same, but I can practice dial ups or hold overs for long range shooting on my short range by using subsonic ammo...