300 BLK Problems and testing

[JSH]

CFEBLK wasn’t around years ago when I was playing with a 300 whisper. One of the most frustrating cartridges I ever played with, trying subsonic out to 200 for the game I was playing. The rainbow trajectory was a royal PITA as far as I was concerned. 50,100 and most of the time 150 was fairly decent to work with.

Best subsonic load I ever had was a Sierra 190GK and a dose of AA#9.

YMMV and use this little input how you will. Oh, my barrel length was 10” and a 14”. The 10” always shot better for me than the 14.

 

[garandman]

OK....much better -

Gun - Sig MCX 8.5" barrel
Load – 208 A-max / 11.2 CFE BLK
Avg – 966
SD - 14
ES – 43

1 – 942
2 – 957
3 – 964
4 – 942
5 – 974
6 – 985
7 – 980
8 – 952
9 – 980
10 – 953

I tweaked the MS sensativity down ( from 6 to 5 ) Next I'll try some Lil'Gun (available locally) and some AA-1680 (look out, HazMat charges)

 

[X-Caveman]

I'm pretty sure the deck height is good. At least this height works well for 338 Norma / 6.5 Cm / 224 Valkyrie.

By this statement^^ do yo mean the MS aluminum check rod is tangent at six O'clock on the suppressor's exit hole the same on your 300 BLK as it does when using the MS on these other calibers? I ask, because you aren't using that same suppressor on those calibers, so the shims are going to have to be adjusted to compensate for the different barrel/ suppressor diameters. Sure you know this, but I figured it was worth asking...

 

[garandman]

By this statement^^ do yo mean the MS aluminum check rod is tangent at six O'clock on the suppressor's exit hole the same on your 300 BLK as it does when using the MS on these other calibers? I ask, because you aren't using that same suppressor on those calibers, so the shims are going to have to be adjusted to compensate for the different barrel/ suppressor diameters. Sure you know this, but I figured it was worth asking...

I just eye-ball it. Bout 1/4" - 3/8" below the bullet path for all involved guns / calibers.

 

[243winxb]

Follow loading data. Make no changes

 

[garandman]

Follow loading data. Make no changes

Hodgdon gave me a max of 11.7 for that 208 A-max. I went with 11.2 and got about 100 fps slower.

 

[dellet]

The problem Is CFE BLK basically is not a good powder for subsonic or low density loads. If you can get some compression on the powder, it completely changes the characteristics.

If you can't get 100% density or close. triple digit ES is the norm. It also leaves so much unburned powder behind that it could be what is being read over the magneto speed or any other chronograph.

This might be of interest
http://www.300blktalk.com/forum/viewtopic.php?f=141&t=100097

 

[garandman]

If you can't get 100% density or close. triple digit ES is the norm. It also leaves so much unburned powder behind that it could be what is being read over the magneto speed or any other chronograph.

Interesting. These cases were noticably MUCH cleaner than the 180 gr Hornady SST's I fired. .

 

[basshusker]

I have an 8.5 inch 300blk upper, run a TBAC suppressor... i couldnt get subsonic to work at all. Gave up. Never used it since, but stuck it away to just develop a full power load for. It was all over the place... best I could get was 205 amax? Subsonic that hit the target, but accuracy sucked still.

Im convinced a rifle barrel is needed for subsonic 300blk. Never played with it sny further yet.

Are you running an adjustable gas block? What settings have you tried if so?

 

[rebel]

I never needed to buy CFE blk because dellet did. After his testing, I figured I would just leave it be. 1680 is old news, works but dirty as hell and louder (suppressed ) than other powders. It comes into the spotlight with heavy supers, clean when compressed a bit. N110 and N120 have proved to be great powders for subs. Gas volume is adequate to cycle AR both pistol and carbine gassed. Try that and see.

 

[garandman]

I never needed to buy CFE blk because dellet did. After his testing, I figured I would just leave it be. 1680 is old news, works but dirty as hell and louder (suppressed ) than other powders. It comes into the spotlight with heavy supers, clean when compressed a bit. N110 and N120 have proved to be great powders for subs. Gas volume is adequate to cycle AR both pistol and carbine gassed. Try that and see.

Got load data?

Tryong Lil'Gun next.

 

[P1ZombieKiller]

I never needed to buy CFE blk because dellet did. After his testing, I figured I would just leave it be. 1680 is old news, works but dirty as hell and louder (suppressed )

I know Lil Gun is dirty.... but I don't find A-1680 as dirty as you are making it sound. Am I missing something?

 

[dellet]

I know Lil Gun is dirty.... but I don't find A-1680 as dirty as you are making it sound. Am I missing something?

It’s all relative.

If you are using pistol gas, you can move to faster powders. In general they will be quieter, cleaner and blow less gas in your face. N120 is a bit of an anomaly. It’s cleaner, and quieter than 1680, with a bit less gas, but not as noticeable as moving to something like H110. It’s a great carbine gas powder.

I find all the Vihtavouri powders to be exceptionally clean and they all now have anti copper agents. All pluses for low density loads.

The other thing N120 has going for it is that it has more bulk for weight and takes just a bit more powder than 1680 to reach the same velocity. Higher load density in slow powders generally produces less ES. That really helps the vertical past 100 yards.

With pistol gas I skip the slower powders all together, there’s just too much muzzle pressure that translates into ejection port pressure and pop along with unburned gas and powder blowing back. Carbine gas needs it to cycle so it’s a different issue.

It s just a great powder that is often overlooked. Partly due to price, partly due to lack of data online, you actually have to invest in a book. Hornady, Sierra and Vihtavouri all have good data.

1680 data works in a pinch, but velocity will be low.

It’s not that 1680 is bad, N120 just has more qualities that I look for, and generally noticeably less vertical at 200 yards and beyond.

 

[rebel]

I know Lil Gun is dirty.... but I don't find A-1680 as dirty as you are making it sound. Am I missing something?

Should have added "when shot suppressed." to that. And yes, it is all relative.

 

[Sniper338]

Are you running an adjustable gas block? What settings have you tried if so?

Id have to look...

 

[garandman]

New load -

Powder Charge: 8.0 gr Lil'Gun
Bullet: 208 A-max
Avg: 982 fps
SD: 13.6
ES: 46 fps

First round registered 2,176 but I omitted it from calcs, and shot 10 more (data above)
Bolt hold open did not catch for this load. Somewhat erratic ejection, short and long. All previous loads locked open. S

AA-1680 and Viht N120 ordered. Trying H4198 tomorrow.

 

[P1ZombieKiller]

New load -

Powder Charge: 8.0 gr Lil'Gun
Bullet: 208 A-max
Avg: 982 fps
SD: 13.6
ES: 46 fps

First round registered 2,176 but I omitted it from calcs, and shot 10 more (data above)
Bolt hold open did not catch for this load. Somewhat erratic ejection, short and long. All previous loads locked open. S

AA-1680 and Viht N120 ordered. Trying H4198 tomorrow.

how did extra testing go?

 

[Swift4Yotes]

FWIW I tried cfe blk in my 6.8 arp barreled ar.
I had to go to .003 more neck tension to get enough tension to hold 90 tnts. It went from no pressure signs to blowing primers and smashing case heads. I'm done with cfe blk.

 

[Coyotefurharvester]

New to the blackout,250 armscor brass on the way. 16" barrel want to shoot 130-150 gr hunting bullets which powder to start with? Not looking to load subsonic.

 

[P1ZombieKiller]

here is where I would start.

http://www.300blktalk.com/forum/ (Read everything by @dellet He has most certainly helped me a lot)

I just switched my hunting rounds over to the Speer Gold Bot 150 grain BO. It is designed to expand at lower speeds.
I am loading mine to 2100 fps, but it tough to get that much powder in my cases.

**** This load works for me in my rifle, but it is above recommended max load****

Remington 700 bolt
16.5" barrel
1:7 twist