300 BLK - Midweight Loads?

[HodakaGA]

I am itching to build a new AR in 300 Blackout, a 16" carbine version.

I've searched the forum for load data and found a lot of subsonic heavy boolit data but very little mid-range loads. I don't think you could get the gun to cycle a light cast boolit (115-135 grain 30 carbine type) so I'm thinking 150-170 grain "30-30" type boolit with a good flat nose, driven pretty hard for southern whitetails, hogs, and just plinking.

Anybody have any good loads like this?

[castblaster]

When I get to my notes l will post the info.


Matt Hooper

[castblaster]

I used info from this to get started
http://www.ar15barrels.com/data/300-221data.pdf


Matt Hooper

[hicard]

castblaster. Where did you get these loads? They really look hot to me, in the 52000+ range. Have you loaded and shot any of them? How did they do?

[L1A1Rocker]

Tagging!

[Bulldogger]

What moulds are you using for those? They look sweet! BDGR

[HodakaGA]

Matt, looking forward to seeing them. The lighter flat-nose is not gas-checked? How's that working. If it works good that would be a super cheap round. Any idea fast can it be driven that way without leading?

I have a 311299 from the NOE group buy a couple of months ago, is that what your other round is loaded with? I planned to use it mostly in my 1903a3.

I'm hopeing to find an accurate 170gr. load at 1900-2000 fps. Am I out of my mind?

[dk17hmr]

I don't think you will get that much velocity out of it, at least I haven't been able to before I am blowing primers. I think I have hit 1650 with 180s. If you want more speed get a box of 125gr nosler ballistic tips, I have got them to 2100 which are great for antelope....or check out the 30HRT.

[leadman]

The velocities listed in that link seem to me to be pretty high. I have been shooting a 300 Whisper for at least 10 years now. I usually load the 125gr BT to about 1,900 fps out of my
18" barrel using W296.
I use 314299, 206grs approx, 11.5grs of WC680, about 1,100 fps. I was told that this will cycle an AR but don't know for sure as my gun is a Contender.

[Moonie]

I used info from this to get started
http://www.ar15barrels.com/data/300-221data.pdf


Matt Hooper

Which of these loads have you tried and of the ones you have tried which ones would cycle the action of an AR-15?

I have all the parts ordered to build my 6.8SPC upper a little brother.

[StratsMan]

Just found this thread, and would like to throw in a couple of cents worth, as I’ve been working up loads for my newly converted 300 Blackout AR…

Quick caveat… these are results and opinions based on my rifle and my loads… YMMV…

First, people talk about this load or that load operating the action in an AR chambered in Whisper vs. Blackout vs. Fireball, etc… I’ve rarely heard people talk about which barrel they’re using, and the size of the vent under the gas block. My barrel is a 16 inch CMMG purchased from Midway, and the gas vent is significantly larger than the vent on my .223 barrel. I’m confident that the extra gas enables my rifle to function normally with loads that other shooters may have trouble with if they have a standard .223 vent on a 300 Blackout barrel.

That said, my last trip to the range included some cast boolit loads using 5744. It was cold and a little windy that day, so I only shot at 25 yards and checked mainly for function. A couple loads were too light to cycle the action, and others were just fine… Using a Lee 200 grain boolit with a gas check, I tried to make it sub-sonic with 10.7 grains of 5744… I’m sure it was sub-sonic, but the action would not cycle reliably. Short stroking; most ejected OK, but the bolt never stripped off the next round in the magazine.

Dropping down in weight to the Lee C123 and a GC, I used 17.5 grains of 5744. This load cycled very smoothly. The primers showed some slight pressure signs. Moving boldly forward, I also loaded boolits from my 311329, about 190 grains with GC, over 17.0 grains of 5744. That was a snappy load! No function problems here, but the primers definitely fill out the pocket. I’ve shot higher pressure loads, but I see no reason to load them this high… I’ll back off in the future.

As far as the loads referenced earlier, the current thinking on other forums is that AA1680 is a good choice for the heavy bullet, sub-sonic loads. H110 seems to be the favorite for small bullets at super-sonic velocities. I’ve used it with small bullets, and it works fine but I don’t think I’ll use it for cast boolit loads.

Currently, Swede at NOE (on this forum) has a 247 grain boolit designed for 300 Whisper scheduled to build next October. Tom at Accurate Molds (www.accuratemolds.com) has a few heavy designs for Whisper/Blackout also. I have one on order, and am anxious to give it a try in my rifle.

[L1A1Rocker]

When I get to my notes l will post the info.


Matt Hooper

Did you ever get your notes on these loads?

[Moonie]

Just found this thread, and would like to throw in a couple of cents worth, as I’ve been working up loads for my newly converted 300 Blackout AR…

Quick caveat… these are results and opinions based on my rifle and my loads… YMMV…

First, people talk about this load or that load operating the action in an AR chambered in Whisper vs. Blackout vs. Fireball, etc… I’ve rarely heard people talk about which barrel they’re using, and the size of the vent under the gas block. My barrel is a 16 inch CMMG purchased from Midway, and the gas vent is significantly larger than the vent on my .223 barrel. I’m confident that the extra gas enables my rifle to function normally with loads that other shooters may have trouble with if they have a standard .223 vent on a 300 Blackout barrel.

That said, my last trip to the range included some cast boolit loads using 5744. It was cold and a little windy that day, so I only shot at 25 yards and checked mainly for function. A couple loads were too light to cycle the action, and others were just fine… Using a Lee 200 grain boolit with a gas check, I tried to make it sub-sonic with 10.7 grains of 5744… I’m sure it was sub-sonic, but the action would not cycle reliably. Short stroking; most ejected OK, but the bolt never stripped off the next round in the magazine.

Dropping down in weight to the Lee C123 and a GC, I used 17.5 grains of 5744. This load cycled very smoothly. The primers showed some slight pressure signs. Moving boldly forward, I also loaded boolits from my 311329, about 190 grains with GC, over 17.0 grains of 5744. That was a snappy load! No function problems here, but the primers definitely fill out the pocket. I’ve shot higher pressure loads, but I see no reason to load them this high… I’ll back off in the future.

As far as the loads referenced earlier, the current thinking on other forums is that AA1680 is a good choice for the heavy bullet, sub-sonic loads. H110 seems to be the favorite for small bullets at super-sonic velocities. I’ve used it with small bullets, and it works fine but I don’t think I’ll use it for cast boolit loads.

Currently, Swede at NOE (on this forum) has a 247 grain boolit designed for 300 Whisper scheduled to build next October. Tom at Accurate Molds (www.accuratemolds.com) has a few heavy designs for Whisper/Blackout also. I have one on order, and am anxious to give it a try in my rifle.

I have the same barrel on order, did you ever get the mold from Tom? I'm very interested in this boolit in this barrel, did you get the one with or without GC? I am planning on getting the one WITH GC as I will probably load it full power in 30-06 as well, and having the GC can only help with accuracy at any speed.

[Idaho Sharpshooter]

I liked the 311247 design so well, I bought a 4-cavity each PB and GC, with one cavity HP'ed.

I have a couple of 30's for it, from BLK to 30-06 to 300 H&H.

I weighed the first batch of each, they were so close in weight and dimensional uniformity, that I don't bother anymore.

[donnis]

Is anyone loading for 300 BLK with a 311299?

I'll be shooting them in a DSA upper in formed LC brass. I won't be using a suppressor and am just looking for accuracy and function (no velocity target).

[Moonie]

Got my mold from Tom at accurate, the 245c, cycles in mine and my sons 300blk carbine gas with 9gr w296. He has cmmg 16" and I have ar stoner 16"

[leadman]

I checked a 300 Whisper with WC680 and filled to the neck it was 19.3 grains with the case tapped on the bench a couple of times. Those other loads would be pretty hot IMO.
Don't think they would be good for a Contender. With the harder mil-spec primers it may be a go in an AR, don't really know though.

[hicard]

donnis, I am using 311299 with good results. I use between 13.5 and 15.5 (yellow range) grs of AA1680 and they function and shoot great.

[StratsMan]

Hicard, did you run those 311299's through a chrony??? I'd sure like to know what kind of velocities you're getting with that much 1680...

Moonie, (post 13)... sorry to be slow to respond... I got my mold from Tom. I was tempted to get the 245, but just had to tweak it so Tom created 235B for me... I've cast with it (aluminum), but haven't gotten to the range to shoot them yet!! Were you able to put a chrony on your W296 loads?? That looks like it would be nice and slow....

[donnis]

Thanks Hicard. Not a powder I have on hand, but I'll pick up a pound.