Can anyone recommend a good load for the 300 acc

[brstevens]

What might be a good starting load for the 300 acc / Blackout that has a 1-10 twist barrel? For a Savage bolt action rifle? :help:

[bc83]

110 gr vmax 19.5 gr H110

[geargrinder]

My AR pistol likes 208g Amax 12g AA1680.

11g of the AA1680 works in my AR rifle but won't lock the bolt open on the last round.

[adammiddagh]

1:10" twist eliminates the heavy bullets. Edit: My 17" 1:8" twist will throw 220/230gr lee cast sideways if I don't get the velocity over a certain point, but they fly fine at say 900fps or faster.

I am playing with some cast bullets.
lee molds. 113gr lfn and 120gr lrn. Powder coated. 4-5 gr of trail boss for subsonic.
Have to crimp into a lube groove to improve feeding. 120 gr lead round nose feeds slightly better.
Light load for when my form1 suppressor stamp shows up.
Would say it feeds correctly about 80% of the time.

I previously worked up a super load for an ar pistol that feeds awesome in my savage.
It was with a 125gr speer tnt hp fb. 18.6gr of lil gun. Est 1998 fps from 10.5" ar barrel.

Also. 110gr speer varm hp fb. 19.3gr of imr 4227. Est 1960 fps from 10.5" ar barrel.

For ar setups. There is a limited powder selection that will cycle the action. Bolt setups are easier to find a good powder for.
For light loads, make sure each bullet leaves the barrel. For the supers, start low and work up for a safe load in your gun. I think my super loads or something similar can be found in hogdons online data.

[brstevens]

Being a bolt action I do not have to worry about the load working the action. What might be the top weight of bullet for this twist?

[adammiddagh]

In the 300 blk velocity, I would suspect 160-185 gr. To be about the heaviest. Others may know better.

[brstevens]

Was thinking about the lee 160gr designed for the 7.62x39 ?

[adammiddagh]

Tried that one also. With 5gr of red dot. Feeds nice. With the powder coat, the nose rides the lands a pinch tight. Sized to 309. The nose is like 307-308 with powder coat. Might be able to go super with gaschecks. And a slower powder.

[adammiddagh]

I am temped to try a noe 125gr mold made for 300blk supers.

[thatguyshm]

Using the Lee 155gr .312" cast bullets, powder coated and GC, I would use 17.0 gr IMR 4227 and it cycled great. Shot them in a pistol and a 16" AR. The rifle would get around 1950 on the chrono.

Shm

[adammiddagh]

What kind of alloy are you using? Must be fairly hard to get max velocities like that.

[thatguyshm]

Using pure lead, mixed with about 2% tin. I tend to mix soft with a heavy hand on ES powder coating. Never had any leading problems.

I push my 357 mag hard, and have done water jug tests, perfect expansion, didn't shed a grain and opened over 200% with an NOE bulldog mold.

[brstevens]

Using the Lee 155gr .312" cast bullets, powder coated and GC, I would use 17.0 gr IMR 4227 and it cycled great. Shot them in a pistol and a 16" AR. The rifle would get around 1950 on the chrono.

Shm


Was this a max. load?

[thatguyshm]

Never went above this, load shot well enough. As accurate as factory ammo, so there was never any need to push it.

[Vanilla Gorilla]

I have an AR-15 in 300blk with a 16" barrel and have had great success with H110 and Nosler 110gr Varmageddons. I can get those as either "blems" or "over runs" from shootersproshop.com for less than the any other 110gr bullets. Seems that the blk like either H110 or W296 for supers and A1680 for subs. I have used IMR4227 for some super loads and it doesn't seem to get the velocities as the other 2 powders i mentioned. There is more out there that you can try but this is just my experience. Hope this helps.

[adammiddagh]

Did some load development yesterday. My cast loads are not where they should be yet, accuracy wise.

But...
My old load using TNT 125gr hpfb shot so well, I chronoed them. I estimated them at 1998fps out of my 10.5" AR Pistol. But, out of my 17" savage, they were 2368fps with 16fps SD.
18.6gr of Hodgdons Lil Gun. 2.100" OAL, .002" crimp. These were loaded on a Lee Loadmaster Progressive Press with Volume powder measure. I had notes in my book that primmers started to flatten at 19.3gr.

I no longer use progressive to load 300 blackout for consistency reasons, especially now that I have gotten rid of the pistol and built a Savage.

Worked my way out to 100, 200, 300, 400. Could not miss at 400 after dialed in, shooting at 8" Gong. Shot once at my 4" gong at 400yds, rolled gong over and wrapped up in chains.

My ballistic software says ~1395fps at 400yds.

At 50yds, the supers hit about 1.2mils high of my subs. The Supers took a total of about 3.5 mils to reach 400yds.

[brstevens]

Interesting, thanks!

[adammiddagh]

As a side note. I noticed that the lil gun powder was leaving a thick, hard glazed coating on the muzzle. When I ran out of lil gun loads, the problem went away. After seeing that, I would not recommend lil gun for the blackout.

[thatguyshm]

I've been reading a bit more on loading the BLK and I've noticed that 4227 comes into its own in midweight 30 cal bullets. 110-125s and you can't pack enough powder in, but with the 150-165 is supposed to be the stuff to use. I forget which magazine I read that in, but it definitely falls in line with what I was seeing.

[brstevens]

Anyone have a load using 4227 with the lee 160 made for the 7.62x39 ?