Advice on subs CFEBLK

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dellet
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Re: Advice on subs CFEBLK

Post by dellet »

Thins is from an old thread when i first tested CFE. Note the velocity spreads and group sizes. This is why in think you can do better with what you have.
viewtopic.php?f=141&t=100097

dellet wrote: Sun Jan 29, 2017 12:46 am Spent a little more time with CFE today, learning the quirks of the powder.

I have probably written it off as a short barrel/pistol gas powder. It is just too loud for me and there are to many better choices.

In a carbine gas I think it has some real potential. The added burn time, longer dwell really tames the noise and cuts down on the amount of powder blow back. There is very low port and muzzle pressure. Still a fair amount of gas.

I wanted to see how light of a bullet that could be cycled, I run an 18" 1/10 twist carbine gassed rifle, port size is .110" with a M16 Lmt enhanced BCG and a JP heavy/tungsten captured spring using the heaviest spring. I set this rifle up for hot supers, I've done a lot to slow down the bolt speed as much as possible.

The fun news is that with this setup I was able to have full function shooting Hornady 150 fmj #3037 bullets when suppressed. This might end up being a very good powder for carbine gassed guns.

Now for the bad news.

Still struggling with high spreads.

Right now my feeling is that this is a powder that needs to be compressed. The initial loads in the original post were by the book. 208 Amax, 11 grains at 2.260". ES in the hundreds. Accuracy in the inches at 50 yards.

I seated the 150 fmj's at the cannelure. 11grn 2.040" COL. Although I had lock back on empty, I had possibly the highest ES/SD numbers in recorded history. An ES of 353, SD 133. The group on the right of the pic below is much better than those numbers indicate. It is only fifty yards, I am quite sure at 100 I would measure it in feet.

Image

The group on the left, starts showing some promise.

Back to the Hornady 208 Amax. 11.5 Grains 2.195 COL.

I started this load like I do many. I always record where the bullet will touch the powder. In this case, with 11.5 grains in the case, bullet seated on the powder, COL is 2.220". I put .025" compression on the powder.

Last week's load of 11 grains at 2.255" had an ES just over 200 fps.

This week 11.5 grains at 2.195" had and ES 56, SD 21. There was one odd round that had a very low velocity. when I discounted that as a possible loading error the ES dropped to 24, SD 10. these are numbers that are a reasonable to start with. The change in the group from last week to this reflects that. Again 5 shots at fifty, for reference that is a 1" dot.

I am feeling a little better about the powder and will try to run a couple more loads this weekend. I need to drop some speed, these were cracking at 25 degrees. It is somewhat encouraging tho.
300 Blackout, not just for sub-sonics.
TRshootem
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Re: Advice on subs CFEBLK

Post by TRshootem »

I found with CFE-BLK that a magnum primer cleared up to a large degree the the wide ES and SD spreads in the testing of subs and supers. I focused my test with 150 gr Gold Dots, and CFE-BLK and 1680 with compressed supers loads. Compressed charges responded very well in accuracy out my RARR, suppressed. I have done a couple tests like Dellets for subs and those seemed to prefer a mag primer as well. The 208 Amax is really a fine shooter as a sub sonic bullet.
TR

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dellet
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Re: Advice on subs CFEBLK

Post by dellet »

TRshootem wrote: Thu Dec 15, 2022 11:26 pm I found with CFE-BLK that a magnum primer cleared up to a large degree the the wide ES and SD spreads in the testing of subs and supers. I focused my test with 150 gr Gold Dots, and CFE-BLK and 1680 with compressed supers loads. Compressed charges responded very well in accuracy out my RARR, suppressed. I have done a couple tests like Dellets for subs and those seemed to prefer a mag primer as well. The 208 Amax is really a fine shooter as a sub sonic bullet.
TR

MERRY CHRISTMAS you all !
I forget sometimes about the magnum primers. It’s all I use.
300 Blackout, not just for sub-sonics.
fancygunz
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Re: Advice on subs CFEBLK

Post by fancygunz »

Ghostman wrote: Tue Dec 13, 2022 8:50 pm I have been loading up some 300 blk with LC Brass and using some Sierra 168grain TMKs. I'm using CFEBLK powder. I know this bullet isn't "designed" for the 300BLK but I bought some a while back when bullets were scarce and think they should work. Also, at sub velocity levels I don't really think any of the advertised bullets expand or explode well from what I have seen others post. After testing the speed on a few different loads this is what I put on paper. The windage drift on these was around .75-1", but elevation was 2.25" at 50 yards. Using a table and bags.

So anyways I'm using a RCBS RC2 press with lee full length sizing dies and I did not taper crimp these. Just using neck tension, seated at 2.20" COAL
I'm using a hand trickler and RCBS digital scale to get 11.5 grains, velocity as follows
917, 942, 949, 979, 995
I am using a suppressor and I also have an adjustable gas block, but it's set to full open and my brass is ejecting at 3:00-3:30 position. The rifle is fully functioning and this tells me I just have the right amount of gas for cycling.

I've read some people state that the CFEBLK likes to be compressed. I'm wondering if I should continue upping the powder charge or am I wasting my time on these bullets? How can I get some more consistency and accuracy. Open to all suggestions. Thanks.
Are you by any chance using a Ballistic Advantage barrel?
popper
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Re: Advice on subs CFEBLK

Post by popper »

powder that needs to be compressed, Or nearly. 2400 is pretty much the same, needs temp and pressure to burn right which means a high fill portion.
Ghostman
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Re: Advice on subs CFEBLK

Post by Ghostman »

fancygunz wrote: Mon Dec 19, 2022 9:02 pm
Ghostman wrote: Tue Dec 13, 2022 8:50 pm I have been loading up some 300 blk with LC Brass and using some Sierra 168grain TMKs. I'm using CFEBLK powder. I know this bullet isn't "designed" for the 300BLK but I bought some a while back when bullets were scarce and think they should work. Also, at sub velocity levels I don't really think any of the advertised bullets expand or explode well from what I have seen others post. After testing the speed on a few different loads this is what I put on paper. The windage drift on these was around .75-1", but elevation was 2.25" at 50 yards. Using a table and bags.

So anyways I'm using a RCBS RC2 press with lee full length sizing dies and I did not taper crimp these. Just using neck tension, seated at 2.20" COAL
I'm using a hand trickler and RCBS digital scale to get 11.5 grains, velocity as follows
917, 942, 949, 979, 995
I am using a suppressor and I also have an adjustable gas block, but it's set to full open and my brass is ejecting at 3:00-3:30 position. The rifle is fully functioning and this tells me I just have the right amount of gas for cycling.

I've read some people state that the CFEBLK likes to be compressed. I'm wondering if I should continue upping the powder charge or am I wasting my time on these bullets? How can I get some more consistency and accuracy. Open to all suggestions. Thanks.
Are you by any chance using a Ballistic Advantage barrel?
I am not using a Ballistic Advantage barrel that I know of. It’s a no name barrel so I’m guessing it’s a BCA. This upper I bought was cheap as hell.

So I found some 175 grain Sub-X bullets. Anyone have any load recommendations? Thinking of trying around 12.0 grains to start out.
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