300 blackout subsonic help

[lav2323]

Looking for some help. I've been loading subsonic 220 gr Sierra HPBT with CFE BLK, I cannot seem to get a stable bullet. Some info about what I am using

10.5 inch upper
1/8 twist
case: LC
Primer SR CCI 400

I've started with 11gn and worked up to what Hodgson says as max for sub which is 12.1gn.
COL I've used Sierras info which was 2.23 and Hodgson which was 2.26. Bullet seems a little more stable with COL of 2.26, but still showing signs of being unstable. Mainly concerned about a baffle strike. I have been testing these rounds at about 5 ft into thick card stock paper.

Anyone here have an experience with CFE BLK and these issues? Should I try a lighter bullet? I believe my rifle twist should be able to handle 220 gr. Thank you!

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[DizzyJ]

What do you mean by unstable? Are they key-holing?

 

[lav2323]

yes, but ever so slightly, its just not a nice round print and can tell its unstable. I shot super sonic rounds next to those prints just to make sure I wasn't going crazy. And the supers were perfect prints.

 

[lav2323]

This is what they all pretty much look like

 

[John Gault]

No experience with that powder or bullet but my Nosler 220 grain HPBT with 11.4 grains of 1680 are amazingly accurate considering a 9" barrel..

I understand your concern. I shot several tests prior to putting my can on for this load..

Willing to send you some of the Hornady 220s if you want to take the bullet out of the equation..

 

[lav2323]

John,

Yeah its a little frustrating, especially since I have a lot of the 220 grain SMK bullets left. Thank you I appreciate the offer though! I might just go down to a 200 grain bullet see what that does. Unless someone else has had this experience before and solved it.

 

[saxon]

also when working with sub loads start high and work down so as to avoid any squib, also

Hodgdon has load data for CFE BLK on-line for every bullet weight from 110 grain to 230 grain.....

That said, I think CFE BLK is too slow for the 300 Blackout, even though it was developed for it. Just looking at the sub-sonic loads the pressures are stupid low. Too low for a complete burn. 13,400 PSI with a Max load with a 208 grain bullet when every other powder listed is 19,900 PSI or above tells me it's going to be dirty in the bore and lots of un-burnt powder about.

Unless you can compress CFE, you will have all the problems described along with high ES/SD numbers and accuracy issues. It's just a poor choice for subs. Supers are reasonable.

 

[edzz]

Pictures or it didn't happen.

This is what they all pretty much look like

View attachment 787672

Looking at how they are printing has me wondering what the impacts would look like if the target had been turned 180 degrees for a few of those shots. What I'm seeing could be due to the grain of the paper.
I would expect the supersonics to 'cut' the paper differently and may display differently on the target.

 

[lav2323]

also when working with sub loads start high and work down so as to avoid any squib, also

Hodgdon has load data for CFE BLK on-line for every bullet weight from 110 grain to 230 grain.....

That said, I think CFE BLK is too slow for the 300 Blackout, even though it was developed for it. Just looking at the sub-sonic loads the pressures are stupid low. Too low for a complete burn. 13,400 PSI with a Max load with a 208 grain bullet when every other powder listed is 19,900 PSI or above tells me it's going to be dirty in the bore and lots of un-burnt powder about.

Unless you can compress CFE, you will have all the problems described along with high ES/SD numbers and accuracy issues. It's just a poor choice for subs. Supers are reasonable.

saxon,

unfortunately this is the only powder I have, just started loading subs. As I'm sure you know finding other powders is pretty difficult now haha. What powder do you recommend for the future?

 

[lav2323]

Pictures or it didn't happen.

Looking at how they are printing has me wondering what the impacts would look like if the target had been turned 180 degrees for a few of those shots. What I'm seeing could be due to the grain of the paper.
I would expect the supersonics to 'cut' the paper differently and may display differently on the target.

I can give it a try see what happens, but as of now I just don't want to take the risk shooting through a can with them looking anything but normal.

 

[edzz]

I can give it a try see what happens, but as of now I just don't want to take the risk shooting through a can with them looking anything but normal.

oops
didn't notice a draft had been saved with the pictures remark, I had started that one as you posted the photos. my bad

 

[saxon]

saxon,

unfortunately this is the only powder I have, just started loading subs. As I'm sure you know finding other powders is pretty difficult now haha. What powder do you recommend for the future?

1680

and for that bullet
H110
4227

 

[BrandonQuixote]

It probably just doesnt like that bullet. I personally have used CFE BLK with decent results, in a 10.5" and currently a 10" 1:8, but high SD. Switched to 1680 and got more consistent. I recently shot the last of the CFE BLK with 220gr berry's and they were fine. I understand the hesitation with the suppressor and possible baffle strikes. I think either changing bullets or playing with your seating depth may help, getting right up to the lands might be a solution to getting better stability, if they're jumping. Are you right at 1050fps? perhaps you're going too slow and not getting the rotational energy for stabilizing those thicc boiz. You could use some W296/H110 for subs as well, but thats probably not the prevailing issue. Also, good luck finding powders.

 

[lav2323]

It probably just doesnt like that bullet. I personally have used CFE BLK with decent results, in a 10.5" and currently a 10" 1:8, but high SD. Switched to 1680 and got more consistent. I recently shot the last of the CFE BLK with 220gr berry's and they were fine. I understand the hesitation with the suppressor and possible baffle strikes. I think either changing bullets or playing with your seating depth may help, getting right up to the lands might be a solution to getting better stability, if they're jumping. Are you right at 1050fps? perhaps you're going too slow and not getting the rotational energy for stabilizing those thicc boiz. You could use some W296/H110 for subs as well, but thats probably not the prevailing issue. Also, good luck finding powders.

not sure on FPS as I don't have a way to measure that right now. But I am on the top end of the load data so I'm thinking it should be fast enough. As far as seating depth did you notice if the powder likes to be compressed more?

 

[BrandonQuixote]

not sure on FPS as I don't have a way to measure that right now. But I am on the top end of the load data so I'm thinking it should be fast enough. As far as seating depth did you notice if the powder likes to be compressed more?

At 11.8gr of cfe you're probably going to get compression seating at 2.20. I tried many bullets and depths and couldn't get good consistency, but never had any stability issues. If you were getting failures to Ignite, I'd say try a magnum primer and if that doesn't work, I'd try a more voluminous powder. These won't solve your stability issues though. Know anyone with a 300blk to try out on? Maybe it's your barrel? When you chamber a round and extract it, are you getting imprints of the lands on the ogive? I'd say load them as long as your magazine will function with and your gun will chamber and see if you stabilize.

 

[lav2323]

At 11.8gr of cfe you're probably going to get compression seating at 2.20. I tried many bullets and depths and couldn't get good consistency, but never had any stability issues. If you were getting failures to Ignite, I'd say try a magnum primer and if that doesn't work, I'd try a more voluminous powder. These won't solve your stability issues though. Know anyone with a 300blk to try out on? Maybe it's your barrel? When you chamber a round and extract it, are you getting imprints of the lands on the ogive? I'd say load them as long as your magazine will function with and your gun will chamber and see if you stabilize.

yeah barrel is pretty new, so other than the 1:8 twist, thinking that could be an issue. And no imprints on the bullet when chambered.
So shot today through some poster board, and did a COL of 2.26 with 11.8gn. It looks alittle better hopefully you can see the picture added, might just be the poster board used as opposed to the other stuff I used in previous photos. Let me know what you think. I do have a buddy with another 300 blk but he has the same twist rate so wouldn't help out much.

 

[DLS]

Try hanging a backer target of different construction about one foot behind the main target. You may just have funky tearing on the original paper target. All bullets oscillate around their axis during flight. The bullet will intercept the backer at a different point in the oscillation giving you a better indication of the bullets stability.

 

[BrandonQuixote]

Granted paper does tend to tear- ergo the development of wadcutter bullets for target shooting. These look much better and seems to be the remedy. Both of my barrels were 1:8, that seems to be the most common. There are faster twists for shorter barrels like Q's but these are just fine for your apparent application.

 

[Member 34319]

Looking for some help. I've been loading subsonic 220 gr Sierra HPBT with CFE BLK, I cannot seem to get a stable bullet. Some info about what I am using

10.5 inch upper
1/8 twist
case: LC
Primer SR CCI 400

I've started with 11gn and worked up to what Hodgson says as max for sub which is 12.1gn.
COL I've used Sierras info which was 2.23 and Hodgson which was 2.26. Bullet seems a little more stable with COL of 2.26, but still showing signs of being unstable. Mainly concerned about a baffle strike. I have been testing these rounds at about 5 ft into thick card stock paper.

Anyone here have an experience with CFE BLK and these issues? Should I try a lighter bullet? I believe my rifle twist should be able to handle 220 gr. Thank you!

It's not the load data, it's your gun.

Your gun may or may not be subsonic with Hodgdons load data or any load data for that matter. Your gun may or may not stabilize any bullet with any load data in any manual. Load data is a reference source, and should aid in finding out what is suitable for your gun.

A chronograph would be a worthy investment if looking to keep subsonic with any gun, especially if it's not stabilizing a bullet you want it to.

My advice is to keep tinkering, get a chronograph, see if you can use more powder to go a bit faster and stay subsonic.

Best of luck!

 

[lav2323]

It's not the load data, it's your gun.

Your gun may or may not be subsonic with Hodgdons load data or any load data for that matter. Your gun may or may not stabilize any bullet with any load data in any manual. Load data is a reference source, and should aid in finding out what is suitable for your gun.

A chronograph would be a worthy investment if looking to keep subsonic with any gun, especially if it's not stabilizing a bullet you want it to.

My advice is to keep tinkering, get a chronograph, see if you can use more powder to go a bit faster and stay subsonic.

Best of luck!

Thanks for the input! that will be my next purchase the chronograph see what I can get away with.