There are some slamming prices on 300 Blackout uppers and pistols kits right now. Brain Says Not needed, The rest of me is "TAKE MY MONEY!" Please help me. I'm so weak.

I've owned two 300blk uppers and ended up selling both of them. but like you i've been definitely contemplating another, despite knowing I don't enjoy it as much as my other ARs in 5.56.

The cool factor will wear off soon! Just remember it's Expensive to shoot especially subsonics !!

The most important consideration with any new rifle/upper is your intended use. Start with this and weigh the benefits and the negatives.

I have a 11.3" barrel Wilson Combat upper. My reasons for buying it:
- I wanted to register one of my lowers as an SBR. IIRC the stamp for my lower lists a 300blk upper with a minimum barrel length of 8".
- I felt the 300blk was a better option for an SBR, due to its advantage in muzzle energy over a short-barrel 223.
- I wanted an AR-15 that I could practice for matches at very close distances on my steel targets, without damaging the steel. I correctly calculated that the 11-ish inch barrel with 150-ish grain 300blk bullets doesn't damage steel, yet retains somewhat decent down-range flight ballistics for longer distance targets.

The positives of my 11" blackout upper:
- It functions fine with all my magazines -- plastic or metal, with both subsonic and supersonic loads.
- For practicing match stages with lots of rounds in a short time, the blackout has the same basic recoil feel as my 223 uppers. I have a 22lr upper for such training, but its minimal recoil changes the dynamics of training.
- The upper can be used for HD, with the proper ammo.

The negatives of my 11" blackout upper:
- Subsonic ammo has poor accuracy. Vertical stringing at 50 yards sucks. By 100 yards it is intolerable. At 25 yards the accuracy is decent, but at that close of target distance even the Mini-14 (the standard-bearer of inaccuracy) produces fairly small groups. Furthermore, most heavy 308 bullets don't expand or tumble at subsonic velocities -- a special bullet is required for any reasonable form of subsonic HD ammo.

- A lot of factory blackout supersonic ammo has pretty dismal accuracy. Not only from my upper, but from rifle competitor buddies who also have 300blk rifles/uppers. Expect a lot of testing before you achieve 223-like accuracy from a 300blk. Best options will include the 110 Hornady Vmax, 125 SMK, or 110/120 Barnes bullets.

- I found that some of the more accurate factory ammo popped primers in my upper, and evidently I'm not the lone ranger here. Popped primers in an AR15 generally means the gun goes down, and the primer has to be fished out of somewhere in the action or trigger. My worst experience was with fairly accurate 125 grain supersonic loads.

- When I actually want to reliably hit a target at 200+ yards with my 300blk, I use only Aussie Outback 125 SMK ammo. Second choice is Hornady 110 VMax -- although I do see some vertical stringing with that load. Barnes 110 Vor-tx ammo flies well, but its copper bullet produces only a tiny pinprick on painted steel, so I don't train with it.

Overall -- I'm OK with purchasing my 300blk upper. It works fine for its specific purpose. Nevertheless, I spend way more time shooting my 223 rifles/uppers.

If you have a .30 cal suppressor, subsonic .300 BLK is a lot of fun.

quote:

Originally posted by fritz:
Furthermore, most heavy 308 bullets don't expand or tumble at subsonic velocities -- a special bullet is required for any reasonable form of subsonic HD ammo.

Even with ammunition that reliably expands at subsonic velocities, my first choice would never be subsonic ammunition in a rifle for defensive purposes.

Anyone who has hunted with both pistols and rifles can tell you that projectiles above about 2400-2600 fps are tremendously more effective than projectiles below that velocity.

Even with good bullets, subsonic .300 BLK is unlikely to be any more effective than 9mm.

I have a SIG MCX in 300 BLK because I wanted a smallish defensive weapon, i.e., “pistol,” in the cartridge. For that purpose, though, I would never deliberately limit its performance by relying on subsonic loads, even if I wanted to turn it into an unwieldly beast with a suppressor. With proper ammunition the cartridge produces as much kinetic energy from 9 inches as a typical 223 load does from 16", and not to mention with a much larger, heavier bullet. If gun size wasn’t an issue in a particular situation I’d still prefer 223 in a carbine, but in tight quarters or when discreet transportation as a handgun is desirable, I don’t believe it’s possible to do better these days than the 300 from a short barrel.

Interesting review on 9mm Vs. 300Blk...

https://youtu.be/XleB3VOXpV8

quote:

Originally posted by dry-fly:
Interesting review on 9mm Vs. 300Blk...

Yes it is, but 115 grain FMJ is hardly a good 9mm bullet for civilian self-defense, so I would not consider that to have been a meaningful comparison.

maladat -- Even with good bullets, subsonic .300 BLK is unlikely to be any more effective than 9mm.

dry-fly -- Interesting review on 9mm Vs. 300Blk

sigfreund -- Yes it is, but 115 grain FMJ is hardly a good 9mm bullet for civilian self-defense, so I would not consider that to have been a meaningful comparison.

****
I don't think everyone is talking apples to apples here.

We all should know that 9mm ammo with FMJ bullets performs poorly compared to modern loads with expanding 9mm bullets in gelatin tests.

Many shooters should know by now that subsonic 300blk loads aren't anything to write home about. A few of the recently developed bullets do OK in gelatin, but the kinetic energy of subsonic 300blk is little more than that from typical handgun loads.

The video dry-fly linked compared 9mm FMJ ammo to a specialized 110 grain supersonic 300blk load. The blackout load produces close to 4 times the muzzle energy of the 9mm FMJ, has a high enough muzzle velocity to produce noticeable temporary wound cavities, and has a bullet that fragments. This is definitely not apples to apples.

Might as well compare 9mm FMJ performance to Hornady's 75 grain TAP in a AR15 carbine.

*****
This is the challenge with 300blk. IMO it started with AAC's rollout promotions of the blackout -- IIRC they compared ballistics from lackluster 55 grain FMJ 223 loads to their wonder-bullet 110-ish grain loads. Woohoo, look what an uber caliber the 300blk is!!!!

I don’t see how Lehigh Defense 300 Blk rounds are inferior to any 9mm, JHP, +P, etc. *at* close range. I don’t think anybody expects 300 Blk to be awesome at distance.

quote:

Originally posted by dry-fly:
I don’t see how Lehigh Defense 300 Blk rounds are inferior to any 9mm, JHP, +P, etc. *at* close range. I don’t think anybody expects 300 Blk to be awesome at distance.

The Lehigh rounds will be vastly superior to any 9mm round, at any range. The Lehigh round is a supersonic rifle round -- the 9mm is a pistol round, regardless of the barrel length the 9mm is shot from.

Supersonic 300blk can be pretty effective at a few hundred yards, with the right bullet, with a long enough barrel to build enough muzzle velocity for down-range performance.

quote:

Originally posted by CandyMan.45:
The cool factor will wear off soon! Just remember it's Expensive to shoot especially subsonics !!

300 BLK is NOT expensive to shoot if you load your won. Odd, and sort of wonderful thing, is that the loading data and powders used are very similar to 357 Magnum. However where 357 Magnums top out at 1900 fps or so from a 20 inch rifle the Blackout can hit 2300 fps with a 125 grain spitzer all day long and it won't leave your shoulder bruised after 50 or 100 rounds down range. BTW, cost runs 15 to 18 cents per round if your loading with basic fmj bullets. Load with the high dollar Nosler hunting bullets and it does get a bit pricey.

Fritz got what I was trying to say, but I think there was otherwise some confusion.

I think some of the supersonic .300 BLK loads would be perfectly reasonable self-defense loads.

My comment wasn't about .300 BLK for HD as such, it was about subsonic rifle rounds for HD.

I've shot deer with Buffalo Bore .41 Magnum loads out of a 6" revolver. I forget, but the specific load was something like a 200 grain bullet at 1600 fps - anyway, a larger diameter, faster, higher-energy projectile than subsonic .300 BLK.

It punched nice, clean holes through deer with little to no damage outside the actual track of the bullet.

For a long time, my deer rifle was a 7mm-08 and I used Hornady "Superformance" ammo - a 139 grain bullet at maybe 2900 fps. It reliably turned the majority of a deer's lungs into something resembling melted strawberry ice cream.

The difference (specifically, the presence or absence of significant tissue damage beyond the actual bullet track) isn't a result of the difference in muzzle energies, it is a result of the different velocities.

If someone is in my house threatening my family, I know which I would rather have.