300 AAC Blackout

[altheating]

What cast boolit and load are you finding shoots best in the 300 AAC BLK? I have made the brass and await the arrival of my upper.

[RU shooter]

so far for me my best load is the RCBS 165 on top of 16.2 grs of Lil Gun for a full power load not as fast but still shoots well are RE 7,H4198 with the Lee 185 and the Lee 155 ,Also the 311299 shoots well with just about anything Ive tried so far

[HodakaGA]

RU Shooter, care to share load data and velocities for your 311299?

[27judge]

i also have the 311299 mold and would like to see your results tks ken

[Mr Humble]

Notice on the Savage Arms website that they have cancelled building a rifle in this caliber. It shot fine with high velocity light bullets but they could not get the subsonic heavy bullets to meet the oft heard claims.
I remember, back when, the 308 1.5", was very accurate with "ordinary" (up to 180 gr.) bullets. (Ken Waters).
This whole subsonic thing is a mystery to me. I doubt 1 in 100 300 Blackout/Whispers are owned by real snipers. Waiting to join the 5mm Remington, SAUMs, 10mm auto and other success stories.
There is a reason real snipers use 308s, 300 WinMags and 338 Lapuas ...... they kill bad guys.

[Tonto]

Round was built for the AR platform. The bolts and Encores help provide something to shoot loads that won't cycle semiauto. I have a DCArms 300AAC upper, I enjoy forming brass, casting bullets and shooting. This is cheap fun. I always liked the 300 Whisper concept but could never afford to get in the game. I snipe rocks on the backstop. I really think Accurate thought this up to sell 1680 powder.

[freddyp]

I only have a bolt gun (mk77) for the Blackout. I tested the Lee 180 and Blue Dot. I started at 7.0gr and stopped at 10.0gr. The 8.0gr and 9.0gr loads shot the best, all touching. At 10.0gr, the groups opened and the cci400 primer was getting flat.

[Moonie]

I've used w296/h110 with the 170gr lee and it worked very well at full power, in subsonic with 245gr the w296/h110 was iffy at best. H4895 has worked well for subsonic 230gr and 245gr boolits but the SD was high, probably due to my powder measure having issues with the stick size.

[RU shooter]

RU Shooter, care to share load data and velocities for your 311299?

Sure ,So far Ive used Lil Gun up to 12 grs and still working up, also used a caseful of 4895( 17 gr.) and both RE 7 and H4198 16-17 gr. 17.5 is about all I can get in the case without deforming the nose alot when seating the bullet, As for speeds? I dont have a chonograph,I had a guy run the one load through quickloads for me though ,It stated with my 20" barrel 17.0 of H4198 would yield 1690 fps with pressures in the low 40K range with a 98% burn to the muzzle. Everything shot to an acceptable accuracy level so far, all loads easily gave positive functioning of the action.

[HodakaGA]

Thanks RU!

[bruce drake]

I bought my 300BLK AR to have a 30 caliber AR that replicates the 7.62x39/30-30Win ballistics. Its a great caliber for deer/pigs and pests with super-sonic loads. I don't build sub-sonic loads.

I'm not a sniper, never proclaimed to be one. But I am a damn good shot

Bruce

[mstarling]

Barrel length, twist, the position of the gas block, and whether or not you want to stay subsonic have a lot to do with loading for the 300 BLK. Really need more info on your rifle and intended outcome.

[Tank56]

Remember, you have to work down for sub sonic loads. Be careful! The danger is that you may stick a boolit in the bore if you start low and work up. For me Unique is the best for subsonic work, but it will not cycle the AR 15 action. I just use it as a straight pull bolt. It's really quiet, even with out a suppressor. The other powder I like in this cartridge is 4227 either IMR or H variety, but I use it mostly with supersonic loads.

[Gunnut 45/454]

I use the Lee 150gr and 170 gr Gas checked designs and the Custom 170 gr mold that is non gas checked.

[Deano]

I have had fantastic results with the Lee 155 .310 bullets and 18 grains of surplus WCC 680. Velocity is 1740 out of my 16" 10 twist barrel.

[Elkins45]

I use the Lee 150gr and 170 gr Gas checked designs and the Custom 170 gr mold that is non gas checked.

Please tell us more about your custom plain based mold. I'm working really hard to try to find a plain based bullet and powder combination that isn't more of a pattern than a group.

So far my results haven't been terribly encouraging. I did get one nice set of groups with the Lee 230 but that was with a load so mild it wouldn't cycle a carbine length action.

My best accuracy results have been with AA2200 data powder. Some have said it is too slow for this round but my experience has been that the slower powders give the best accuracy.

[nooneimportant]

Some load notes



1680 - 12 gr 247 cast NOE

1170
1151
1143
1137
1155

not a bad spread, it was cracking supersonic or at least transonic with the can on. i think our speed limit is going to be at 1000 fps.

rem 220 smk
1095
1070
1041
1062
1101

1680 12g - 247 noe cast
not subsonic

1151 1160 1172 1153
1156 1158 1170 1137
1142 1165 1124 1155
1153 1161 1151 1180
1144 1097 1165 1171

viht n110 7.7 gr - 208 amax

1010
1000
1009
1001
1011

1680 9.8g - 220 nosler partition
no data recorded but was subsonic to the ear

viht n110 7.1g - 208 amax
no data recorded but was subsonic to the ear

viht n110 7.2 gr - 220 nosler partition
no data but was subsonic to the ear

viht n110 7.4g - 208 amax
no data recorded but was subsonic to the ear

imr 4227 9.3g - 247 noe

1067 1075 1094
1067 1060 1083
1080 1073 1062
1062 1092 1044
1060 1084 1097

1680 9.8g - 208 amax
no data recorded

1680 10g - 247 NOE
for the life of me i could not get a good reading, and have no idea why.


After looking at the 50 yd targets, taking some measurements of the projectiles and running #'s against a twist rate calculator, we are on the edge of what a 1:8 can do with little to no margin for error.

Lots of target photos but I will have to host them somewhere first.

[Gunnut 45/454]

Elkins45
Well so far it's been a bust! Started out with Lil"gun supper load got a scatter gun group so I dropped down to 9.5 gr to see if I could run them as subs Got on paper at 25 yards with 12 gr but not great 4-6" groups and full fuction of AR. Switch to IMR 4227 staying sub at 11.8gr I got function without lockback o nempty and about 2.5" group at 25 yards -not stellar but useable. At 12gr groups opened up again. I'm still working on this one and got some more ideas to get them to work. Conversely I loaded up some of the Lee 170gr GC at the same loading and printed a nice .75" groupd at 25 yards for 10 shots. This is using a reddot -not scoped.

[smokinfeathers]

I'm using 9.5 gr of 4227 with a 200gr n it works the action n locks back the action on empty mag. 16" carbine with carbine gas system with AAC cyclone

[RU shooter]

Elkins45
Well so far it's been a bust! Started out with Lil"gun supper load got a scatter gun group so I dropped down to 9.5 gr to see if I could run them as subs Got on paper at 25 yards with 12 gr but not great 4-6" groups and full fuction of AR. Switch to IMR 4227 staying sub at 11.8gr I got function without lockback o nempty and about 2.5" group at 25 yards -not stellar but useable. At 12gr groups opened up again. I'm still working on this one and got some more ideas to get them to work. Conversely I loaded up some of the Lee 170gr GC at the same loading and printed a nice .75" groupd at 25 yards for 10 shots. This is using a reddot -not scoped.

Have you tried any slower powders like RE7 or 4198 for your super loads or sub loads for that matter? Ive been using both with good results .May not generate top vel. but seems to shoot real well with cast bullets .