300 blackout............good, bad or indifferent??

[3inSlugger]

I'm in the process of an 8" 300BLK SBR that will be suppressed eventually. From what I understand, 300BLK develops full velocity within 9". A big advantage for CQB or brush gun IMO. Especially if you're still getting AK ballistics from a 9" AR-accurate platform.

 

[beastep]

Good point. Im thinking about another blackout in a 10.5" gun.

 

[Mad Professor]

From what I understand, 300BLK develops full velocity within 9". A big advantage for CQB or brush gun IMO. Especially if you're still getting AK ballistics from a 9" AR-accurate platform.

Maybe this is the case with supers, but my experience with the 220gr subs don't reflect this. Fired from a 16" barrel I'm seeing 200fps more than my 9" barrel.

 

[3inSlugger]

Maybe this is the case with supers, but my experience with the 220gr subs don't reflect this. Fired from a 16" barrel I'm seeing 200fps more than my 9" barrel.

I haven't seen that, but possible. However, at the cost of some inefficiency in powder, you could upload your subs a bit to compensate, and also ensure more reliable cycling.

 

[beastep]

Interesting. I havent shot any subs over a chrono I dont think. Just supers.

 

[Mad Professor]

I need to test again some time. Run some supers and also include my 12.5" barrel. The factory ammo isn't very consistent.




MagnetoSpeed XFR Results...
Series: 300blk 220. 11.2 1680 9" Barrel
Sierra bullet, 2.020 OAL

Device: V3
Sensitivity: 5
Units: ft/s


Shots: 6
Max : 945
Min : 918
ES : 27
Avg : 928
SD : 10
1: 945
2: 930
3: 935
4: 918
5: 918
6: 926


MagnetoSpeed XFR Results...
Series: 300blk 220 Rem Fact 9" Barrel
Remington Factory Subsonic 220gr

Device: V3
Sensitivity: 5
Units: ft/s


Shots: 5
Max : 971
Min : 869
ES : 102
Avg : 922
SD : 43
1: 869
2: 971
3: 944
4: 946
5: 884


MagnetoSpeed XFR Results...
Series: 300blk 220 11.2 1680 16" Barrel
Sierra bullet, 2.020 OAL


Device: V3
Sensitivity: 5
Units: ft/s
Shots: 5
Max : 1120
Min : 1095
ES : 25
Avg : 1105
SD : 9
1: 1106
2: 1120
3: 1107
4: 1099
5: 1095


MagnetoSpeed XFR Results...
Series: 300blk 220 Rem Fact 16" Barrel
Remington Factory Subsonic 220gr

Device: V3
Sensitivity: 5
Units: ft/s
Shots: 5
Max : 1167
Min : 1091
ES : 76
Avg : 1126
SD : 33
1: 1129
2: 1167
3: 1150
4: 1091
5: 1096

 

[Mad Professor]

I haven't seen that, but possible. However, at the cost of some inefficiency in powder, you could upload your subs a bit to compensate, and also ensure more reliable cycling.

Depending on desires you could load it up. Cycling has not been an issue in any on my combinations. Suppressed or not, but I primarily shoot suppressed with 300 BLK. The below tests were unsuppressed.

 

[Perplexed]

If you do not hunt, or reload, or shoot suppressed, is there a good reason for the 300 BLK round?

 

[adamsredlines]

Maybe its dumb luck...but my 300 outshoots my 5.56.

 

[NikatKimber]

If you do not hunt, or reload, or shoot suppressed, is there a good reason for the 300 BLK round?

I would say most of the reasons are negated given those conditions.