300 Blackout load data and questions

[6Creed73]

Any luck with W 296? Seems like it would be good sub and super. I’ve been gradually collecting 300 blk dies and brass etc. I just haven’t pulled the trigger on it yet.

W296 is the same powder as H110. It's odd that sometimes I'll see manufacturers load data list slightly different powder charges between the two for the same bullet...but I'm 99.9% sure the powders are identical.

With that said, some people have very good results with H110 for subsonic loads...but for me, I get cycling issues loading H110 for subs, but love it for supers.

 

[Mastershot]

I run in mine the following
10.5 gr imr 4227
hornady 208 gr
cci nato primers

Mine cycle all day long no jams or stove pipes. Speed is just 1050 fps on 8 inch barrel.

 

[rkwells63]

I have a question, why would A1680 be a better powder? Same velocity at a higher pressure than cfe black as per Hodgdon reloading site? If you have not seen their website just look it up. Plus its free.

AA1680 and CFE BLK will both work for subsonic loads in an AR. They are about the only powders that produce enough gas to reliably cycle the action, without using an adjustable gas block. I have 2 subsonic loads for 300 BLK. One using AA 1680 and the other using CFE BLK, both loads use the Hornady 190 gr Sub-X bullet. Both loads use a Small Rifle mag primer and are 3 tenths of a grain apart in charge weight. I have taken several wild hogs with these loads. My rifle has a 16" inch barrel and I use around 11.5 grains of these powders (I'm being vague on purpose), you will have to adjust your charge for the shorter barrel to get to the speed you want. My loads chronograph at 1061 and 1065 fps. The CFE BLK gives a little better ES/SD numbers but both shoot about 1 inch groups at 100 yds. I hope this helps.

 

[Dave in WI]

I don’t know if you’ve tried this, but I would take that 11 grain load and start shortening the COL. Your groups started tightening up and the SD started settling in. Most likely due to higher load density.
Get the base of the bullet in the powder. The higher load density will push the velocity back up. The SMK is incredibly jump tolerant, use that to your advantage.

@dellet Do you have recommended powders for subsonic in 16" BOLT rifle?

 

[DHD]

Playing with a 10" (Criterion) Rainier Ultra Match barreled SBR and now a RAR, I've been hard headed and just use H110 for both subs and supers. That little Ultra Match barreled SBR spanks the RAR (but the barrel costs almost as much as the RAR so....).

Dellet pointed out about changing seating depths to increase/decrease space in the case. My usual game is longer distance accuracy and the 300BO can be counter intuitive to what I normally do for all of the other calibers I play with. The RAR has a throat that is in the next zip code and getting bullets close, like I usually do, makes me scratch my head. Seated deeper and accuracy starts to happen (not what I am used to for sure). This is probably what he was talking about. I'm referring to 208's and 220 SMK's subsonic.

110-125 grain Supers do work well closer to the leade. It's like it's 2 different cartridges.

Luckily the SBR could care less as it isn't picky. I shoot both at 100 yards but have 600 yards to play with. I won't go beyond 300 with subs or supers. I can be frustrated many other ways....

 

[6Creed73]

Playing with a 10" (Criterion) Rainier Ultra Match barreled SBR and now a RAR, I've been hard headed and just use H110 for both subs and supers. That little Ultra Match barreled SBR spanks the RAR (but the barrel costs almost as much as the RAR so....).

Dellet pointed out about changing seating depths to increase/decrease space in the case. My usual game is longer distance accuracy and the 300BO can be counter intuitive to what I normally do for all of the other calibers I play with. The RAR has a throat that is in the next zip code and getting bullets close, like I usually do, makes me scratch my head. Seated deeper and accuracy starts to happen (not what I am used to for sure). This is probably what he was talking about. I'm referring to 208's and 220 SMK's subsonic.

110-125 grain Supers do work well closer to the leade. It's like it's 2 different cartridges.

Luckily the SBR could care less as it isn't picky. I shoot both at 100 yards but have 600 yards to play with. I won't go beyond 300 with subs or supers. I can be frustrated many other ways....

I try to lightly compress all of my 300blk loads. I don't know why exactly, but they shoot better. With the bigger bullets, I usually don't have a choice anyway, I'm pretty much always in the powder with those.

Anyone loading 300blk should keep a piece of brass around with an expanded neck that you can drop a bullet into. I use one to measure how compressed I am. I'll drop a bullet in the test case where it's just sitting on top of the powder and take a cbto measurement. Then when I seat a bullet in the real loads to my desired length, I can compare to see how compressed I am

 

[dellet]

@dellet Do you have recommended powders for subsonic in 16" BOLT rifle?

Yes and no.......

My favorite by far for heavier bullets 190 grains and up, is N105. Sadly it’s supposed to discontinued by Vihtavouri. It works well in both hand fed and gas guns. Burns clean, is quiet will run a gas gun with pistol gas. It has very high pressure and will obturate the base of copper solids.

Probably go back to #9 when I run out of N105.

Some of the lower pressure powders, will gas cut the base of a copper bullet because there is not enough pressure the expand the bullet and seal the bore.

Tinstar is another good candidate, but again on the Vihtavouri kill list.

Lighter bullets, trailboss can work. Just never seemed to be all that accurate.

Accurate #5 is a good candidate as is #2 for the lighter bullets. Old Whisper data has both those powders listed a lot.

One of the best things I ever did was treat bolt actions and AR’s as completely different cartridges. Then subs and supers. You end up loading for such different parameters that they really have very little in common.
Quickload is a very good investment.

 

[Steve Donlon]

I have a DDM Hunter 300 BLK rifle I bought with the intent of having a modern M1 carbine. It has surpassed my expectations. Finally found the right load for me. The 125 Speer TNT's and 130 Varment bullets will shoot moa at 300 yards. That's my range I shoot. But the 125 gr. Sierra 125 gr. MK with 18.3 grs. of 296 will shoot 1" groups at 300 yards. I never thought it was possible. I'm sold on the 300 BLK, a modern M1 Carbine for my needs. Easy to clean, no recoil and the barrel will last a long time.. I found that with only a drop of oil here and there, it runs much cleaner than rubbing oil all over. No need for much oil. I tear down the BCG every time and make sure the firing pin channel is clean using a pipe cleaner, scrap all the carbon off everything with a small knife and steel wool and a little carbon remover. Same as my AR15 but a lot less work with the 300. The 296 powder works best for my needs. Tried some others but always come back to 296 for 125-130 gr supersonic loads.