My wife’s family has 10 acres of land that backs up to more forest with no houses for at least 2-3 miles. Unfortunately, most of it is not cleared, but this area makes a good little area to shoot. Hurricane Michael knocked down so many trees, I am not worried about rounds going astray.

Anyway, I wanted to see what my 190gr subs would do to a cinder block and was kind of underwhelmed. I shot from 50yds away. The first shot went through the first part of the cinder block, but was stopped by the back portion of the block. Round 2 went through the same hole but was also stopped by the back of the block. Round 3 finally penetrated the block and weakened it enough that the next 4 rounds was able to blow it apart pretty well.

This round would probably be pretty effective on two legged predators, but I think soft body armor would probably stop it with great pain to the person wearing it .

I was able to recover what was left of the first two rounds as it was still inside the block before the next 5 rds were fired.

Shooting subsonic is fun, but I’ll stick to my 110gr VMAX and 125gr Speer TNT for serious work.













It’s hard to see, but there is a wall of downed trees about 10yds into the woods.

This message has been edited. Last edited by: usncorpsman,

My 300blk has an 11.3" barrel. I bought to have my first SBR, and to be able to shoot AR500 targets at close range without dimpling the steel while using a round that similar recoil to a 223 Remy. It works fine for this role.

I've test a fair amount of factory subsonic and supersonic 300blk ammo.
- Subsonic ammo has been underwhelming. FMJ varieties have produced erratic accuracy. Hornady's 190 Sub-x and 208 Amax have shown some promise with accuracy, but almost every 5-round group has one low flier. In general, the vertical stringing of subsonic ammo is quite bad -- even for ammo with low SD variation for muzzle velocity. Subsonic 300blk generally produces muzzle energy of a little over 500 foot pounds. Higher than commonly used pistol rounds, but not a huge difference.

- Supersonic FMJ ammo in the 140-150 grain ballpark has shown worse accuracy than 55 grain FMJ in 223 Remy. If I want to train up close on steel, not worrying about longer range accuracy, this works. MV tends to be 2000-ish fps range, which means that even just a few yards from AR500 steel won't result in steel damage.

- Supersonic ammo with quality bullets in the 110-125 grain ballpark shoots quite accurately. My best experience is with 110 Vmax, 110 Barnes, and 125 HPBT. Muzzle energies are respectable here. 1200-1300 foot pounds for the 125 HPBT loads, and 1350 foot pounds for the 110 Vmax. Accuracy is good to 300-400 yards, although with more drop and drift than 223 match loads.

I don't find subsonic 300blk all that useful. For many people wanting an AR-platform rifle/SBR with suppressed subsonic ammo, a 9mm AR using 147 subsonic loads might be a better option.

quote:

Subsonic 300blk generally produces muzzle energy of a little over 500 foot pounds.

I wouldn't expect that to do a lot of damage to a cinder block.