Working down a load for 247gr 300blk - Advice needed

[Skullet]

I have been reloading 300 blackout using the supersonic j things but I finally am ready to start working up loads for subsonic loads using the NOE 247 grain 311 bullet. These will be sized to 310 and be lubed with Ben's red. the target gun for this load will be an AR with a 16" barrel and a carbine gas system. I understand that cycling with that gas port may be an issue on this without a can.

This will be my first time "working down" a load and wanted to make sure that I have my ducks in a row. Currently I have a very little a1680 and more 'lil gun on hand. I was looking around and couldn't find a starting load for these two powders with that bullet. Is there anyone loading these today that might be able to provide a starting point for charges to work from?

Thanks in advance for the advice.

[Jupiter7]

About 10grs of either is a good start point. Most likely lil gun at this amount will be slightly supersonic. Depending on gas port size, neither may cycle.

[reed1911]

If you can get H110/W296, WC297, or 4227 roughly 10-10.5g is a good sub-sonic load. The 4227 tends to burn a little hotter, but unless you are doing lots of rapid fire you will not notice a difference.

[Skullet]

I have some h110 on the shelf as that is what I use on the supers with 147 milsurp. I might give that a try as well.


What does everyone use for coal on this cartridge?

[nrc]

10.5 grains AA1680 chrony's consistently at 970 fps from my 11.5" AR15 with a 208 grain jbullet. As stated above - 10.0 is a good place to start.

In both my AR and my 10" TC, AA1680 provided better accuracy than H110 or WW296, which suprised me. Your results may vary.

[Jupiter7]

I guess this is where we insert the warning about downloading h110. It is known to be very position sensitive and known to have pressure spikes when buring unevenly. I'd save it for supers. Also will most likely go supersonic before cycling your gun as it lacks gas pressure at the port like lil gun, RL7, 4227 and a1680.

[Skullet]

I guess this is where we insert the warning about downloading h110. It is known to be very position sensitive and known to have pressure spikes when buring unevenly. I'd save it for supers. Also will most likely go supersonic before cycling your gun as it lacks gas pressure at the port like lil gun, RL7, 4227 and a1680.

Thanks for that heads up.

[Skullet]

finally had a chance to get to the range today with the chrono. This was my first ladder starting at 10.0 and working down:



Date
3/30/2014






Gun
16" carbine length






Temp
62






Case trim length
1.355






Primer
Wolf SRP






Bullet
247 gn fp Noe Mold






Lube
Ben's Red






Powder
Lil Gun






Charge
10.0
9.7
9.4
9.1
8.9


Shot
FPS
FPS
FPS
FPS
FPS


1
1259
1239
1204
1143
1158


2
1238
1211
1184
1166
1161


3
1269
1193
1191
1151
1167


4
1279
1195
1193
1176
1171


5
1266
1218
1195
1177
ftf










Avg
1,262.20
1,211.20
1,193.40
1,162.60
1,164.25


ES
41
46
20
34
13


Std Dev
15.32
18.79
7.23
15.14
5.85



Obviously I still have a ways to go to get it subsonic but wanted to throw this out for everyone. For the next trip I plan to start at 8.9 and work down to 6.8 in .3 steps.

[Viper225]

I have been searching for a post like this one.
We just cut off the last of the remington 223 cases yesterday and have them formed.
We have a couple boxes of 245 grains from Missouri Mullet Company to play with.
Pretty much the same set up, a 16 Inch AR.
I have been looking for Alliant 300MP Heavy Bullet loads, without much luck so far.

You did not mention if your Lil Gun load was working the action on that AR.

Bob

[Moonie]

RL7 also works well for subs

[Skullet]

I have been searching for a post like this one.
We just cut off the last of the remington 223 cases yesterday and have them formed.
We have a couple boxes of 245 grains from Missouri Mullet Company to play with.
Pretty much the same set up, a 16 Inch AR.
I have been looking for Alliant 300MP Heavy Bullet loads, without much luck so far.

You did not mention if your Lil Gun load was working the action on that AR.

Bob

they quit cycling at 9.7. i will be opening up the gas port and putting on a adjustable gas block to make this work.

[Skullet]

got some more range time and made it to sub sonic finally..

As always YMMV and this is not load data you should use and don't blame me i am just some dumb guy on the internet.....



Date
4/6/2014






Temp
59






Case trim length
1.355






Primer
Wolf






Bullet
247 gn fp Noe Mold






Lube
Ben's Red






Powder
Lil Gun






Charge
8.9
8.6
8.3
8.0
7.7


Shot
FPS
FPS
FPS
FPS
FPS


1
1132
1146
1091
1078
1047


2
1146
1122
1082
1084
1046


3
1163
1107
1091
1084
1033


4
1138
1121
1123
1063
1047


5
1150
1151
1098
1067
1045










Avg
1,145.80
1,129.40
1,097.00
1,075.20
1,043.60


ES
31
44
41
21
14


Std Dev
11.88
18.50
15.60
9.73
5.98




101836101837

Hoping to work on the gas system this weekend and reconfirm the chrono numbers when fully cycling.

[redbullitt]

Those velocities look similar to what i get, but just a little lower. Same lube too.
I am sure it has to do with the fact that I am using a bolt.

Very nice SD on that lower loading, especially if you toss out that oddball 1033 load lol.

I am hopefully getting out to shoot the whisper in the next couple of days and play with that 247 a bit more. Still not happy with the groupings really, but considering I am pretty new to casting I should not complain too much.

Waiting on my plain base gas check maker to see if that makes as noticeable change. Are you running a gas check?

[Skullet]

Are you running a gas check?

plain pb base...

[Teddy (punchie)]

Interested in loads for this mold to. Have a improved 30 cal. With one inch free bore. Was thinking of working up a load and using as a single shot, as I don't think the action or magazine will hold the shells and or work to chamber the rounds.