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]

http://img.tapatalk.com/a6cd095a-b1b3-fc5d.jpg

http://img.tapatalk.com/a6cd095a-b1da-2547.jpg

http://img.tapatalk.com/a6cd095a-b205-aaf2.jpg


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]

http://img.tapatalk.com/a6cd095a-b1b3-fc5d.jpg

http://img.tapatalk.com/a6cd095a-b1da-2547.jpg

http://img.tapatalk.com/a6cd095a-b205-aaf2.jpg


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.

[Greg]

.300 Whisper & Cast

I have some loads that I worked up for my 10" Contender that ya’ll might look at


R-P - Fireball brass necked up
R-P - 7½ primers

Lyman 311679 cast 95-3-2 water quenched
sized .311 / Hornady GC - 208 grains

14.8 grains AA1680;
I had gone up higher but this was the sweet spot for accuracy,
round primers and easy extraction.

1530 fps in a 10" Contender

~~~~~~~~~~~~~
R-P - Fireball brass necked up
W-W - SPM primers

RCBS 30-150 FN cast 50:50 WW & lead
sized .311 / Hornady GC - 160 grains

18.4 grains AA1680;
I had gone up higher but this was the sweet spot for accuracy,
round primers and easy extraction.

2080 fps in a 10" Contender

the RCBS cast at .309 it was borrowed, so it went back…I had Dan at Mountain Moulds cut me a copy to drop at .311/.301
I still shoot this boolit / load.

[HodakaGA]

Thanks for the load data. Keep it coming.

I have one or 2 full cans of WW680. Of course I'd work up loads, but can't it be substituted for AA1680?

[StratsMan]

My burn rate chart shows XMP5744 much closer to WW680... both slower than 1680, but the burn rate chart doesn't tell you everything!!! I have used 5744 in mid-range 300 BLK loads... They cycle my AR just fine... Don't have a chrony, so not sure about velocities...

Using a Lee C312-155 mold (for 7.62x39) and sizing at .311, 17.5grains of 5744 cycled smoothly and recoil was mild... IF I had any WW680, and was gonna load with this bullet, I'd drop that down a bit, say to 16.0 grains, and start working up from there.

[Greg]

any internet load should be double checked against a loading manual

then start 10 % below and work up slowly

[StratsMan]

any internet load should be double checked against a loading manual then start 10 % below and work up slowly

Greg, that's a good rule to follow if you can find a recipe from a loading manual... The SAAMI spec for 300 BLK is new enough that not everyone has published data yet... I've not done an exhaustive search, but I wasn't able to find loading data for 300 Blackout at the Accurate website...

If anyone knows where it's published, please share....

[donnis]

Exactly what I was thinking. Hodgdon has some data and I'd also trust the recent Guns and Ammo article. Haven't see much other "official" data.

[Johnk454]

Just getting started myself, so not a lot of info to share. Loaded these Lyman 311041s today over a starting load of 297. Hope to find a good spot around 1800fps, but we will see.


http://home.comcast.net/~johnk454/300BLK311041.jpg

[Greg]

Hornady and Sierra both have published loading data for the .300 Whisper ~ email them

American Rifleman ~ May 2008 ~ .300 Whisper

Hodgdon has 300 AAC Blackout data ~ on line

[Gunnut 45/454]

My main plinking /target load will be the Lee 150 gr GC over 16.5 gr of IMR4227. Chronied out of my 16" CMMG I'm getting 1829 fps!

[Greg]

a short American Rifleman article on the .300 Whisper is here...

http://www.americanrifleman.org/m-articlepage.aspx?id=1368&cid=31

[sparky45]

Just getting started myself, so not a lot of info to share. Loaded these Lyman 311041s today over a starting load of 297. Hope to find a good spot around 1800fps, but we will see.


http://home.comcast.net/~johnk454/300BLK311041.jpg

What Dies are you using John? BTW, VERY nice looking rounds.
Sparky

[27judge]

im thinking of a 300 blackout upper from cmmg ,what can one expect in accuracy 25 to 50 yards with cast bullets. i have a lyman 311291 and a rcbs 180sp both with gas checks and a pile of 1680 and 2015 would like to hear any input. this would be a play/plinker rifle as i have a upper from white oak in 223 and another from dtech in 6x45 for any long range shooting tks for your time ken

[sparky45]

I was notified by Midwayusa that my CMMG 300 blackout upper was shipped last Friday, can't hardly wait. I have the Lyman 311291 to use and some Sierra 110gr BTHP's to try as well. I have a number of different pwds. to try but will stay with H110 and maybe some Trailboss. Any load data for cast would be appreciated.

[StratsMan]

I have a 300 BLK CMMG barrel from Midway, that I assembled the way I want it... when I load up my 235 grain GC boolit (Accurate Arms #31-235B) and get it up to high sub-sonic velocity (appx 1000 - 1100 fps), with AA1680, my 5-shot group dropped down significantly... covered with a quarter.... (25 yds)

I'm confident the barrel and load are more capable than I....

Of course, YMMV.....

[leadman]

I had both a 1 in 10 and a 1 in 8 twist barrels for my Contender. The 1/10 was a 10" and the 1/8 is 18". The 10" barrels would match the velocities for the 18" with the same pressure signs.
So pay attention to what twist the load was worked up in.
T/C barrels are 1 in 10 twist.